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REPORT ON A YEAR'S WORK IN BACTERIOLOGICAL 
 DIAGNOSIS OF DIPHTHERIA. 
 
 BY 
 
 WYATT JOHNSTON, M.D., 
 
 Bacteriologist to the Board of Health for the Province of Quebec : Pathologist to the 
 
 Montreal General Hospital. 
 
 {Reprinted from the Montreal Medical Journal, My, 1896.) 
 
REPORT ON 
 A YEAR'S WORK IN BACTERIOLOGICAL DIAGNOSIS 
 
 OF DIPHTHERIA.' 
 
 BY 
 
 Wyatt Johnmton, M.D., 
 Bacteriologist to the Board of Health for the Province of Quebec ; Pathologist to the 
 
 Montreal General Hospital. 
 
 Until a year ago no considerable number of bacteriological exami- 
 nations had been made of diphtheria cases in Montreal. During the 
 twelve months ending March 31st, 1896, there were sent from the 
 two laboratories of which I have charge, 998 samples of exudation 
 examined as to the presence of the diphtheria bacilli. Of those 528 
 were examined at the Provincial Board Laboratory, including samples 
 from all cases admitted into the diphtheria wards of the Catholic 
 section of the Civic Infectious Hospital, and 470 at the General 
 Hospital Pathological Laboratory, including samples from each case 
 admitted as diphtheria into the Protestant section of the Civic Hos- 
 pital. 
 
 The examination was made by me personally in 729 cases. The 
 remainder were examined by either Dr. J. E. Laberge (128), Dr. W. 
 H. Jamieson (89), Dr. J. A. Williams (5), or the late Dr. E. P. Williams 
 (47), who at one time or another kindly undertook my work during 
 my illness or absence. 
 
 Methods — The methods followed were in the main those adopted by 
 the New York Board of Health, which was the first sanitary body to 
 introduce a system of wholesale bacteriological examination in diag- 
 nosing diphtheria. The fact that this precedent has been followed 
 within two years by the establishment of similar services in many 
 large American and European towns, and that in no case have any 
 very important modifications or improvements been introduced 
 speaks volumes for the efficacy of the system originated by Drs. H, 
 M. Biggs and W. H. Park. 
 
 The Board of Health of the Province of Quebec considered that 
 cheap card-board boxes which could be destroyed when once used 
 would be preferable to the more elaborate outfits in use elsewhere 
 and in view of the greater uniformity of results obtained the Board 
 has only issued outfits with swabs, the cultures being made in 
 the laboratory. Suitable blanks for filling in reports. are sent out 
 
 1 Read before the Montreal Medico-Chirurgical Society, April 3rd, ]»<16. 
 
4 
 
 with each outHt and these outHts are left at pharmacies conveniently 
 situated for all parts of the city. The fact that the service was a pro- 
 vincial and not a municipal one made it necessary tliat we should not 
 atteujpt to do more for Montreal than we were pr(!pared to do for the 
 entire province, and therefore the enforcing of quarantine and local 
 notification ari-angements are not attempted, nor is a daily collection 
 made from the depots, as should certainly be done in the case of a 
 municipal diphtlieria service. 
 
 Unfortunately the absence of permission to use the mails for trans- 
 mitting samples of throat exudate has made it difficult to get samples 
 to tht) lalx)ratory in time for sending a report on the following day, 
 and this has often prevented physicians from availing themselves of 
 the facilities ottered by the Provincial Board of Health. 
 
 Preparation of thetnedliivi^ — I have employed throughout LiBffler 
 serum, made by adding J volume of alkaline, 1 p.e peptone, 1 p.c. 
 glucose beef broth to ox-blood serum, simultaneously sterilized and 
 coagulated in a water oven. (Hueppes method.) This medium gives 
 a good growth at the end of 12 to 14 hours. The trouble and delay 
 of frequent visits to the abattoir has been avoided by preparing large 
 quantities of the serum at a time, adding with the glucose bouillon as 
 a preservative, 1 to 2 per cent, chloroform and keeping it in self- 
 sealing preserve jars until required for filling the tubes. I have used 
 this method (suggested originally by Koch) since 1892 with very 
 satisfactory results, and have still a reserve supply of serum kept by 
 this means in ordinary corked vials since 1892, which was recently 
 tested and found to yield a satisfactory medium. 
 
 It may be well to mention that if the serum contains much blood 
 this will form a compact layer over the chloroform in the bottom hence 
 it is better to shake the jar occeisionally during the first few days. 
 
 By wrapping tin-foil round the tops of the tubes and dipping them 
 into paraffin, they may be kept indefinitely without drying up. The 
 tin-foil prevents the paraffin from entering the cotton wool. I owe 
 the sufifffestion to Dr. Adami. 
 
 Method of taking samples — A small galvanized iron rod with a piece 
 of cotton wool is twisted round the end sterilized and placed in a 
 sterilized tube, enclosed in a card- board box, with directions for use, 
 forms the outfit of the Provincial Laboratory. In the case of the 
 General Hospital Laboratory, a serum tube, for making the culture at 
 once, is sent with the swab. 
 
 1 Hard boiled eggs have been used as a culture medium from time to time when 
 we happened lo be short of scrum in the laboratory, but I found they require more 
 time and skill in order to properly make culture than is the case with the serum 
 sterilized in tnbes. 
 
5 
 
 It is better not only to rub the surface of tlie exudate witli the 
 swab but also to p.t«s the swab alonjr under one edge of the exudate 
 MacLollum), as bacilli may sometimes be met with in this situation 
 atter they have disappeared from the surface. In cases of laryngeal 
 or nasal diphtheria, the bacilli are usually present in the umcus on the 
 posterior wall of the pharynx. In case of negative results innocula- 
 tion should be made, if possible, with pieces of membrane. It must 
 be borne in mind that in some cases of diphtheritic croup, the bacilli 
 may only appear late in the disease. 
 
 The use of ordinary cotton wool (as recommended by Shuttleworth) 
 IS preferable to absorbent cotton. The swabs should be thorouiihlv 
 sterilized before use. 
 
 The result of the examination is communicated by mail, and also 
 by telephone if desired, by noon on the day following the receipt of 
 the swab at the laboratory. 
 
 In the cases of an anomalous growth or none at all on the serum. 
 1 have been in the habit of examining th'3 swab micro.scopically but 
 my experience is in accord with that of Park, that the routine ex- 
 amination of the swab in all cases seldom gives additional information 
 or enables a certain conclusion to be arrived at earlier than by the 
 ordinary culture methods. The direct microscopic examination is a 
 work which falls vithin the province of the clinician rather than of 
 the laboratory bacteriologist. 
 
 I have tabulated 882 samples received during the twelve months 
 ending March 1. 1896. Of these 572, or 64 per cent., were primary 
 examinations or first samples and 310 secondary .samples examined 
 subsequently, either to determine when the throat became clear from 
 bacilli in the genuine cases, or for the further study of doubtful ones. 
 
 i«Q /fo ^"""^""^ '^"'P^'''' '^^^ ^^^ P^' ^*^"*^) «^^^ positive results ; 
 18J (33 per cent.) negative results, and 52 (11 per cent.Uloubtful 
 results. So that we had to deal presumably with rather more than 
 dZl cases of genuine diphtheria. 
 
 The relative frequency of mixed infection is shown from the fol- 
 lowing table of primary samples : 
 
 Klebs-LosfBer bacilli in pure culture 43 pe^ cent. 
 
 with streptococci 15 » 
 
 „ " with Htaphylococci and streptococci 13 " 
 
 staphylococci alone 10 " 
 
 pneuniococci 5 » 
 
 Short bacilli and other combinations ^['.. .....['.]'.[[ 4 
 
 100 
 Untortunately I had no opportunities for determining the relative 
 mortality of the different associations and my information as to the 
 
6 
 
 relative benefits from antitoxin in each is too fragmentary to have any 
 value. 
 
 Persistence of Infection in the Throat— Oi 310 re-examinations or 
 secondary cultures, made to see whether the bacilli had disappeared 
 from the throat in the later stages or in the event of a doubtful result 
 in a primary culture, 145 or 47 per cent, gave positive results. Among 
 these there was only one case (E. C.) where the bacilli were missed 
 at the first examination and found subsequently. This was a case of 
 laryngeal diphtheria following pharyngeal, where the case was first 
 examined bacteriologically on the ninth day of the illness. As a rule 
 the bacilli become scanty in a membrane that has been formed more 
 than four days, though in some cases they were abundantly present 
 for several weeks after the disappearance of the membrane, and in 
 two cases virulent bacilli vvcre still present four weeks after the 
 throat had been quite free from membrane. 
 
 On the other hand, they were absent in about one-half the cases by 
 the third day after the disappearance of the membrane, corresponding 
 with the statement made by Park. Unoer these circumstances the 
 advantages of a quarantine regulated by bacteriological examinations 
 over one with an arbitrary time limit is obvious. 
 
 In cases treated with antitoxin the bacilli persisted as long in the 
 throat as those treated without antitoxin. Personally, from what is 
 known of the biology of the diphtheria bacillus and especially its 
 tendency to die out or fail to increase in the presence of very weak 
 acids, I should favour some mild treatment by lozenges or confection 
 containing a weak organic acid, such as citric acid, by which an acid 
 condition of the fauces could be kept up would be the most promising 
 way of getting rid of the bacilli, but I have had no opportunity of 
 testing this. I notice also that no note is made of the reaction of the 
 fauces with reference to the persistence of bacilli. 
 
 Significance of Negative Results— With regard to the significance 
 of a negative result, it depends altogether upon the stage at which 
 the sample is taken. In case of negative results we have always 
 requested the sending of secondary samples if anything in the course 
 of the case tended to show that the case was really diphtheria. The 
 result in these cases was almost universally negative. Out of 189 
 cases with negative results I have been able to hear of but two cases, 
 where a visible membrane gave negative bacteriological results in the 
 early stage, being followed by diphtherial paralysis. 
 
 The chief difficulty to the bacteriologist in interpreting these 
 negative results is the absence of certain information that the sample 
 has been properly taken. The occurrence of diphtherial paralysis 
 
I regard as conclusive evidence that the case was really diphtheria. 
 When the clinical diagnosis i. positive I think that even after 
 negative bacterial results, samples should be taken at intervals 
 ot a day or two in case of a re-infection. In any case, a negative 
 result shows that the exudate is not at the tin^e in a state likely to 
 spread infection. *^ 
 
 It was not found, as a rule, that the taking of duplicate samples at 
 the same tune gave any additional information, though in one case 
 bac.ll, were absent in one sample and present in a duplicate taken 
 at the same tune. Additional samples taken after an interval of 12 
 to 24 hours were more often of service. 
 
 In any case where the patient has been ill for four or Hve days the 
 absence of bacilli in the cultures, even from visible membrane, should 
 not be considered as proving that the case is not one of diphtheria. 
 When the sample is taken from cases with no visible membrane the 
 negative results are less trustworthy, but as a rule in cases of croup 
 the posterior wall of the pharynx gives an abundant growth of diph- 
 theria bacilli. Some throat swabs taken from fatal cases of croup not 
 diagnosed during life were found to give positive results, a method 
 which might be made to yield valuable statistical information in a 
 properly managed system of death certiQcation. The fact that so- 
 cailed simple croup is credited with causing in Montreal double the 
 number of deaths due to typhoid should make this question worth 
 investigation. 
 
 Donhtful Results-ln 11 per cent, of the primary cases the results 
 otthehrst culture were not decisive ; of these 1 percent, showed 
 entire absence of growth, due to the use of antiseptic applications 
 shortly before taking the sample. Sometimes organisms, apparently 
 characteristic Klebs-Lceffler bacilli, were present in such small num- 
 bers that they did not correspond with the known tendency of 
 diphtheritic bacilli to rapid growth as compared with other organ- 
 isms. In such cases a second culture was uniformly asked for and 
 obtained, but it was just as uniformly negative, except when obtained 
 m the late stages. If one is sure that the sample, properly taken 
 from visible membrane in an early stage, gives negative results, there 
 IS very httle danger of the case being diphtheria. With regard to 
 the late cases in which few bacilli are met with, it is likely at all 
 even s that the danger of infection will be as slight, so long as the 
 bacilh are scanty in the exudate. 
 
 The routine advice has been to keep such cases isolated and send 
 further samples. In case they are exposed to danger of infection 
 from undoubted cases of diphtheria, or removed to an infectious 
 
8 
 
 hospital, a small dose of antitoxin would confer immunity. This- 
 power of innnuni/.ation offsets to some extent the lack of any proper 
 isolating wards for observation of doubiful cases in our contagious 
 hospital. With a scanty growth of suspicious looking bacilli, I am 
 inclined now to look upon the case as probably not diphtheria, if in 
 an early, or probably not highly infectious if in a later stage. As 
 severe angina so often proves to bo a manifestation or complication 
 of scarlatina or some other exanthem, I favour isolation in a fever 
 hospital, if not obtainable otherwise, as being the safest plan for the 
 public safety. The clinical course of these ca.ses, however, often 
 shows them to be tonsillitis by the end of 24 or 48 hours. My exper- 
 ience of such cases has been decidedly that they are not infectious. They 
 usually improve suddenly if left to themselves, and so if a dose of anti- 
 toxin happens to be taken this may create the impression that the case 
 was really diphtheria. The absence from the cultures of a sufficient 
 number of streptococci to explain the condition of pseudo-membranous 
 angina is suspicious of diphtheria, as most of the non-diphtheritic 
 anginas are due to streptococci. As I have information about several 
 cases, not diphtheria, benefited by antitoxin, I think its employment 
 in all doubtful cases should be the rule if the symptoms are grave, 
 especially if there are evidences of croup. * Our experience in the Hos- 
 pital laboratory has been that an unusual number of doubtful results 
 were found in connection with private cases. It was the rule in such 
 cases to find a considerable number of suspicious looking bacilli in 
 many cases which we did not consider to be diphtheria. The only 
 explanation which suggests itself to me is, that the samples were 
 taken in these cases with unusual care, and an unusually liberal 
 amount of the exudate was smeared on the culture media, and that 
 under these circumstances a certain amount of growth in the natural 
 secretions of the pharynx may have been possible with germs which 
 do not grow on Ltefller serum. Sometimes, where the growth was 
 scanty, portions of the exudate itself would be removed from the 
 serum in examining the culture. The presence of bacilli in the 
 exudate, which do not grow on the media, is against the probability 
 of diphtheria. 
 
 An abundant growth is sometimes found of a bacillus which does 
 not have the typical characters of Klebs-Loeflfler bacilli. 
 
 These cultures constituted between 1 and 2 per cent, of all the 
 samples examined and were extremely puzzling. They usually occur 
 in groups, and are associated with contact or exposure to genuine 
 diphtheria. None of them were fatal in my experience, though two 
 or three were followed by pharyngeal paralysis. The membrane 
 
9 
 
 formation was described as not being typical but usually thick and 
 pultaceous, and in 8ouio cases no distinct niembrune was formed. 
 
 In one such case, the rather large organism met with grew on 
 potatot>s as a distinct white colony, excluding it from the category of 
 Klebs-Lu'ttler bacilli. It killed guinea pigs by septicjemia without 
 the characteristic hoBmorrhagic infiltration of the diphtheria bacilli. 
 
 In the case of genuine diphtheria bacilli, a certain proportion of the 
 rods stain intensely, almost black, with warm carl)ol fuchsin. In the 
 ease of the pseudo-forms this was not the case, the staining being 
 more uniform and much fainter. 
 
 In another case an organism forming long rods was obtained in 
 pure culture and killed guinea pigs in the typical manner with the 
 characteristic lesions. 
 
 In a third case, without any diphtheritic membrane, an organism 
 was met with which was twice as long and thicker than the Klebs- 
 Lceffler bacillus in the first culture, but on making sub-cultures in 
 successive generations became typical, and later on showed typical 
 growth from secondary throat cultures. 
 
 This tendency of bacilli, when in considerable amount in the first 
 cultures, to revert to the well-known Klebs-Lfieffler type in sub- 
 cultures and their tendency to show virulence to guinea pigs, has 
 made it hard to decide that any bacillus is not Klebs-Lceffler bacillus 
 if it IS found in abundance in a primary culture, no matter how far it 
 may be removed from the orthodox standard morphologically. 
 
 The most satisfactory mode of procedure is, of course, the in- 
 oculation of guinea pigs, but to do this properly involves delay. In 
 the first place, the original throat cultures are nearly always too 
 thickly sown to allow of the immediate isolation of pure cultures 
 without preliminary separation upon surface of serum tubes which 
 means usually a delay of a day. When a pure culture is obtained 
 conclusive results can only be assured by inoculation of a bouillon 
 culture, which means a delay of one or two days more. Finally, if 
 the full degree of virulence is not present, the animal may take two 
 or three days to die. In any case, as pointed out by Roux and Yersin 
 and by Park, the fact that one colony grown from a sample is not 
 virulent, does not show that another of the same bacillus from the same 
 case may not be, as the virulence of diflFerent coloAies, even in the 
 same case, has been shown to vary greatly. The formation of acid 
 oralkahcan be more readily determined, but also- requires isolation 
 of pure cultures in order to be used. 
 
 The delay and trouble attendant on this test by inoculation contrasts 
 very unfavourably with the convenience and rapidity of the rest of 
 the technique for quarantine purposes. I have obtained more satis- ■ 
 
10 
 
 factory results from simply making secondary cultures; it will be 
 found either that the bacilli are absent from the cultures or that more 
 typical forms are met with. 
 
 Where there is definite growth of bacilli from the throat, the case 
 should be provisionally regarded as one of diphtheria until shown to 
 be otherwise, whether the clinical symptoms and the morphological 
 characters are typical or not, as the tendency to variability is far 
 more distinctive of the diphtheria bacillus than any one of the forms 
 in which it occurs. 
 
 Visible growths on acid potato, or motility and formation of alkali 
 are sufficient to characterize any organism showing them as some- 
 thing else than the Lceffler bacilli. 
 
 Significance of Positive Results. — When a typical heavy growth of 
 a bacillus, corresponding in appeaiance with the Klebs bacillus, is met 
 with, there need be no hesitation in declaring that the conditions for 
 diphtheritic infection rvQ present, whether the clinical symptoms cor- 
 respond or not, anc^ er there is visible membrane or not. 
 
 Of the 293 prima pies examined at the Provincial Board of 
 
 Health Laboratory, f^, or 13 per cent., were from cases diagnosed 
 clinically as follicular tonsillitis, quite apart from a number more 
 where the diagnosis was stated to be possibly or probably diphtheria. 
 Of these 43 cases diagnosed as tonsillitis, 19, or 45 per cent., were 
 shown to be diphtheria. This result was confirmed by inoculation 
 experiments in a number of my earlier cases, the result being uniformly 
 positive in every case where it waa tried. This experience tends to 
 shake one's confidence considerably as to the efficiency of the diagnosis 
 of tonsillitis from diphtheria without making cultures. As to the 
 recognition of diphtheria from tonsillitis, of 293 primary samples sent 
 to the Provincial Bacteriological Laboratory, only 173, or 59 per cent., 
 gave positive results, and of 279 primary specimens sent to the patho- 
 logical laboratory of the Montreal General Hospital only 148, or 53 per 
 cent., gave positive results. Possibly many of these were only sent as 
 an additional precaution in cases clinically considered as tonsillitis, but 
 we found that cases called follicular tonsillitis were really diphtheria 
 45 times out of 100. 
 
 We may assume that when a patient is sent to a diphtheria ward 
 in an infectious hospital some good grounds exist for diagnosing the 
 case, but in the case of the Catholic division of the infectious hospi- 
 tal of 73 primary samples from cases sent as diphtheria, only 46, or 
 66 per cent., showed the presence of diphtheria bacilli, while 25 or 
 over .showed none. 
 
 In the case of the Protestant section of 92 primary samples, 81, or 
 
11 
 
 87 per cent., showed the presence of diphtheria bacilli and 11, or 13 
 per cent., showed none. The difference between the results of the 
 two sections appears to be due to the fact that a preliminary bacterio- 
 logical examination was made in a large number of patients at 
 the Montreal General Hospital before forwarding cases recommended 
 for admission as diphtheria. 
 
 From the above, I have omitted from the negative result in each 
 division, two patients admitted in the paralytic stage of undoubted 
 attacks of diphtheria, but from whose throats the bacilli could no 
 longer be ol)tained. 
 
 The results go to show the advisability of making, whenever possi- 
 ble, preliminary bacteriological examinations of eases before sending 
 them to the infectious hospitals, and also of providing properly iso- 
 lated observation wards in the infectious hospitals for the reception 
 of doubtful cases. A precautionary immunising dose of serum will 
 considerably lessen the danger of an infection resulting from mistakes 
 in diagnosis, but it will not wholly guard against it as I have met 
 with several instances of diphtheria infection, confirmed by bac- 
 terial examination, among persons supposed to be protected by dos6s 
 of the antitoxin. 
 
 Accuracy of Various Methods of Diagnosis. — The delicacy of the 
 positive clinical diagnosis of diphtheria has been seen in our 572 cases 
 to be sjmewhat over 60 per cent. The bacteriological diagnosis has, 
 in my experience, shown an accuracy of somewhat over 90 per cent., 
 that is to say, a doubtful opinion had to be given in one case out of 
 every ten primary samples examined, and the subsequent course of 
 the cases usually showed them not to have been diphtheria. The chief 
 difficulty in giving a diagnosis is the uncertainty from not having 
 personally fnade the cultures. * I found a greater uniformity of the 
 results in the Provincial Laboiatory where all the tubes are inoculated 
 by one attendant who strictly followed my instructions, than in the 
 hospital laboratory where they were made by various physicians. 
 
 Probably had specimens been indiscriminately sent me in all cases 
 the percentage of genuine cases would have been greater, but naturally 
 one had a preponderance of the obscure cases as, by some physicians, 
 samples were only sent from those which were puzzling. 
 
 The positive results were equally frequent in the case of the 
 hospital cases, where cultures were made at once on serum and for- 
 warded to the laboratory, and in those of the Provincial Laboratory, 
 
 * In one case shown by autopsy to be laryngeal diphtheria a physician inoculated 
 a tube which gave negative results. A few hours later in performing a tracheotomy 
 on the same case he accidentally inoculated his own hand, producing a sloughing 
 wound from which we obtained a pure culture of Klebs Luutfier bacilli. 
 
12 
 
 where the swabs were sent to the laboratory and the culture made as 
 a rule only after several hours delay. 
 
 Diphtheria Bacilli in the Throat of Apparently Healthy Persona— 
 The occasional occurrence of bacilli, like the diphtheria bacillus, so- 
 called pseudo-diphtheria bacilli, in the throat of apparently healthy 
 persons appears to have received an undue amount of attention with 
 reference to its practical bearing upon the diagnosis of diphtheria. 
 These bacilli have very seldom been met with in the overwhelming 
 numbers Avhich characterize the early stages of diphtherial infection, 
 and therefore are not likely to give rise to serious errors of diagnosis 
 in cases examined early. 
 
 On the other hand, it has been abundantly demonstrated that the 
 virulent diphtheria bacilli may exist in large numbers in the throat 
 of persons who are apparently healthy and who certainly do not 
 present any of the clinical features of diphtheria, and this important 
 discovery viewed in its true light should materally influence one's 
 course in dealing with outbreaks of this disease in households or 
 public institutions such as schools, hospitals and asylums. 
 
 Instead of isolating and examining bacteriologically only those 
 cases which have sore throat, all the throats in the institution or 
 household should be examined bacteriologically and those persons 
 from whom a culture of diphtheria bacilli is obtained should be 
 isolated and quarantined, whether they are ill or not, until no bacilli 
 are found in the throat cultures. 
 
 This is probably the explanation of the difficulty often experi- 
 enced in preventing the spread of diphtheria in households or public 
 institutions, even after all persons actually ill have been rigidly 
 quarantined. 
 
 Attention to this mode of infection by the New York Board of 
 Health has led to most satisfactory quarantine results, and Aaser, of 
 Copenhagen, has recently reported an outbreak in a cavalry regiment 
 which continued to spread after all the sick persons had been isolated 
 and thorough disinfection performed, and was only controlled when 
 19 persons, apparently healthy, but whose throats furnished growths 
 of diphtheria bacilli, were quarantined. 
 
 Use of Antitoxin.— The twelve months under consideration, cover 
 pretty accurately well the first twelve months' experience with the 
 use of antitoxin and therefore the first years in which a specific rem- 
 edy was available for the treatment of this disease. It is of special 
 interest to study the frequency of diphtheria in the city during this 
 period and see what effect this new remedy, whose efficacy is un- 
 doubted, has had upon the diphtheria death rate. 
 
 
 
18 
 
 From the recbrds at the City Health Office, to which Dr. Laberge, 
 City Health Officer, kindly gave me access, I find that during the 
 period in question 849 cases of diphtheria and diphtheritic croup were 
 reported at the health office, besides 83 cases reported as simple croup. 
 The mortality from diphtheria and diphtheritic croup was 282, and 
 in addition there were 100 deaths from so-called simple croup. Prob- 
 ably three-fourths of the cases of this latter disease were really 
 diphtheria. In Montreal the term of " simple croup " was recently 
 invented to cover obscure throat eases in which notification is per- 
 missible but not obligatory, in the hope that it may lead to cases 
 being reported which would otherwise not be heard of. If the cases 
 thus reported were examined bacteriologically valuable information 
 would be obtained. The deaths registered under this heading, in spite 
 of its harmless and reassuring sound, are twice as many as those 
 occurring from typhoid fever in Montreal. 
 
 The total mortality for diphtheria and croup was thus in the neigh- 
 bourhood of 400 for the twelve months under consideration and 
 double that observed in any one year since 1888, the mortality 
 from diphtheria and croup in the intervening years being as follows • 
 1888,427; 1889,200; 1890,170; 1891,78; 1892,54- 1893 65- 
 1894,99; 1895,419. 
 
 Without going into the proportion of the deaths in the different 
 years to the increasing varying population of the city, I wish to call 
 attention to the fact that during the first year of the antitoxin treat- 
 ment, and in spite of the fact that this treatment was very generally 
 carried out in private patients who could afford it and among hospital 
 patients who get it without paying, and while special statistics show 
 a decided lowering in the death rate, nevertheless in Montreal, twice 
 as many persons died from diphtheria during 1895 as during any of 
 the previous six years. This probably does not depend at all upon 
 any better enforcement of notification in diphtheria cases, as it in- 
 cludes both diphtheria and croup. 
 
 My reason for emphasizing this is to show that the rigorous enforce- 
 ment of the standard quarantine measures of isolation and disinfection 
 is not rendered less necessary by the introduction of the new 
 specific remedy. Indeed I consider that by converting a severe 
 disease into a mild one the tendency of the patients to go about 
 before the danger of infection had disappeared must be increased to 
 an extent which offers a new element of danger, unless quarantine is 
 very strictly enforced. Even physicians hardly realize the necessity 
 of enforcing a tedious quarantine and isolation for what has appar- 
 ently been trivial illness which improved promptly under antitoxin. 
 
14 
 
 Another matter which calls for notice is the practice of withholding 
 antitoxin until the diagnosis of diphtheria is clear. Probably a large 
 proportion of the deaths from diphtli lia arose from delay in the use 
 of this remedy. One would think it better that the remedy should 
 be given ninety -nine times to persons not having diphtheria than to 
 omit it in one genuine case. 
 
 I was often told that a report was wanted in order to determine 
 whether it is necessary to use the antitoxin or not. The invariable 
 answer has been not to delay the administration of antitoxin for a 
 bacteriological report if the case is at all urgent. Although the 
 coincidence of the discovery of this remedy has led to an increased 
 interest in the diagnosis of diphtheria, the unavoidable delay of 15 
 to 24 hours makes it inadvisable to delay a preliminary " protective " 
 dose of the remedy until the diagnosis has been confirmed. In any 
 case, observations have shown marked benefit in certain forms of 
 angina solely due to staphylococci and streptococci when diphtheria 
 bacilli were found to be absent. 
 
 Conclusiorw. — 1. The culture method enables a positive diagnosis 
 to be made in 90 per cent, of all cases of diphtheria when seen early . 
 
 2. The significance attaching to a negative result depends entirely 
 upon the length of time which has elapsed since the onset of the 
 disease, and the absence of bacilli from a case which has lasted often 
 four or five days does not prove that it is not diphtheria ; in any 
 case where the course of disease makes it likely to be diphtheria, 
 repeated re-examination should be made. 
 
 3. In severe cases of suspicious angina, it is advisable not to delay 
 the preliminary dose of antitoxin in order to learn the result of the 
 bacteriological examination. 
 
 4. The greatest value of the bacteriological examination is in deter- 
 mining the necessity and the duration of isolation and quarantine, 
 and if cases continue to appear, the throats of all persons exposed to 
 contagion should be examined whether they show signs of disease, 
 or not, A swabbing to be taken post-mortem in all cases of death from 
 croup. 
 
 5. The patients should not be released from quarantine and the 
 final disinfection of the premises should not be done until the bacilli 
 have disappeared entirely from the affected part. 
 
 6. The bacilli have been shown to infect articles of clothing, furni- 
 ture, etc., and these should be thoroughly disinfected, preferably by 
 steam under pressure, and solutions of mercuric chloride. Fumiga- 
 tion by sulphur is unreliable in the majority of cases as commonly 
 canned out. 
 
 
IS 
 
 noL^r"fr"f''-''T'/,?'T"' "' '""""■ °" »"'™'"'" 20 hour., 
 not quite of the typical Klebs-Lceffller type, should be regarded as 
 
 ™uitendant 1 T\ : "• ",'"'=' ^'^'"' ""^ "f '"'""' of 'he medi- 
 cal attendant and the bactenologist, it is preferable when a case i, 
 
 t3r /'".f"'^ ^ non-diphtheritic shows a g„,wth o^ ZZu 
 tha the further tests of acid production and pari.ogenes i, Tb ' 
 applied, the med.cal attendant being informed of the susp ciou 
 
 hi? f K r^^f ""'' "' *^ "^»»'"y <"■ '-'""on pc.nding Ze 
 thorough bacteriological study. This would remove a coinmof cause 
 
 laTSlT^" """ Tf"" '"''"^■"" "»«' '"« Health Offl 
 and lead to the more careful study of the doubtful cases. 
 
 8. In spite of the use of antitoxin and the great benefits resulting 
 d^lXry^^f °' ^'^-"'-^^ '- g-tl/increased in^ ZlS