UNIVERSITY OF CALIFORNIA
COLLEGE OF AGRICULTURE
AGRICULTURAL EXPERIMENT STATION
BERKELEY, CALIFORNIA
CIRCULAR 322
August, 1931
AN INFECTIOUS BRAIN DISEASE OF
HORSES AND MULES
{Encephalomyelitis )
C. M. HARING,i J. A. HOWARTH, 2 and K. F. MEYER3
A rapidly spreading" disease of horses and mules prevailed in the
San Joaquin Valley of California from July to November, 1930
(fig. 1A), and reappeared in several widely separated parts of the
state in July, 1931 (fig. IB). The malady is apparently identical with
the horse disease which at different times during the past sixty years
has caused heavy losses in various parts of the United States, particu-
larly in the west central states, and has been called ' ' Kansas-Nebraska
horse plague," and also, incorrectly, "cerebrospinal meningitis,' '
ft nonpurulent encephalitis, " "forage poisoning" and "botulism." 4
Studies by Meyer, Haring, and Howitt 5 at the University of Cali-
fornia have shown that the present epizootic in California horses
is caused by a filter-passing virus which produces an inflammation
in the brain (encephalitis) and also in the spinal cord (myelitis).
Accordingly, the suitable medical name for the disease should be
encephalomyelitis. 6
i Professor of Veterinary Science and Veterinarian in the Experiment Station.
2 Associate in Veterinary Science.
3 Professor of Bacteriology, Director of the Hooper Foundation, and Director
of Research in the National Canners' Association Laboratory.
4 Botulism is a poisoning caused by eating spoiled material in which toxins
have been formed by the growth of various types of Clostridium botulinus. The
symptoms in horses somewhat resemble encephalomyelitis but otherwise the
diseases are not related.
s Meyer, K. F., O. M. Haring, and B. Howitt. Newer knowledge of the
neurotropic virus infections of the horse. Jour. Amer. Vet. Med. Assoc. In
press.
6 In Germany a similar disease has been known for many years, and is called
"Borna disease" after a town in Saxony. This disease of horses in Germany
is also caused by a filterable virus which produces an inflammation in the
central nervous system, but which is probably not identical with the American
virus.
University of California — Experiment Station
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Cir. 322] An Infectious Brain Disease of Horses and Mules 3
The following statements regarding epizootic encephalomyelitis in
horses and mules represent the present concensus of opinion of Cali-
fornia veterinarians who have had experience with the disease. These
* J Mi . .# ,
Fig. 2. — Sleepy type.
Fig. 3. — Walking type.
recommendations have been prepared for emergency publication to
furnish immediately-needed information to horse owners. It is antici-
pated that in a few months more information will be available.
University of California — Experiment Station
CHARACTERISTICS OF THE DISEASE
Animals Affected. — Horses and mules are the only animals that
have been observed to contract the disease under farm conditions. 7
Age and sex do not seem to be limiting factors. Stallions, as well as
geldings and mares, and suckling colts, as well as aged horses, are
susceptible. No cases have been reported in this state in animals other
than those kept on farms. The disease thus far has been confined to
those sections where the land is more or less cultivated, and to date no
losses have been reported to the writers in range animals outside of
irrigated or farming districts or in horses kept in city stables, such as
riding academies, except in certain cases recently brought in from
the country.
Symptoms. — In severe cases the animals fall down and are unable
to get up or roll over. They lie on their sides, convulsively paw the
air and ground and bang their heads against the ground, causing
severe bruising especially over the eye. In advanced stages the horses
are relatively quiet.
Inability to swallow, spasms of the muscles of the face, neck (fig. 9) ,
and limbs severe grinding of the teeth, a bubbling noise in the throat
and very foul-smelling breath are characteristic of advanced, acute
cases. Such animals if unable to rise are hopeless and should be
destroyed for humane reasons.
In milder cases the animals stagger, sway from front to rear while
standing, tend to lean against supporting objects, and frequently
grind their teeth or yawn (fig. 8). Two quite different types are
common : the sleepy type, which drowses until disturbed, when it fre-
quently becomes convulsive ; and the walking type, which continues to
pace round and round (figs. 2 and 3). If in a field, such cases usually
follow close to the fence and only change direction when they come in
contact with an obstacle or a turn in the fence. When undisturbed,
some stand with the head against a wall or fence (figs. 4 and 5).
Recognition of the first symptoms is of importance because the
chances of recovery are greater in animals that are carefully treated
and nursed from the very beginning. Unwillingness to be led, lack
7 Experiments at the University of California have shown that the infective
virus which is present in the central nervous system of the sick horses can
produce the disease in horses, monkeys, rabbits, guinea pigs, rats, and mice
when it is injected directly into the brain, and in some instances when dropped
into the nostrils or injected subcutaneously.
Or. 322] An Infectious Brain Disease of Horses and Mules 5
of spirit, slightly wobbly gait, failure to come when called, or, in
unbroken colts, failure to run when approached, are indications. In
some animals the first symptoms are a peculiar tightness of the lips ;
in other cases, the lips are abnormally loose, or twisted to one side
Fig. 4. — Stance when undisturbed, case B-24.
Fig. 5. — Stance when disturbed, case B-24.
(figs. 6 and 7). In advanced stages of the disease, the temperature is
usually normal unless complications, such as pneumonia, have set in,
but in the early stages the temperature may range from 99° Fahren-
heit (normal) to 107° F, according to the individual case.
6 University of California — Experiment Station
The Spread of the Disease. — The disease spread rapidly during- the
months of July and August, 1930, when it invaded all of the horse-
raising areas in the San Joaquin Valley. During the following three
months, the spread to new areas ceased, but heavy losses continued in
the sections already affected. With the advent of cool weather in
Fig. 6. — A, Tightening- of the lips and dilation of the nostrils often continues
through the course of the disease, as in this case.
B, Looseness of the lips may be one of the first symptoms, as in this case.
A B
Fig. 7. — A, Spasm of the facial muscles may cause wrinkling of the muzzle,
as in this case.
B, Muzzle twisted toward the right, caused by left facial paralysis.
October and November, the disease disappeared. During the following
winter and spring, only occasional cases were reported, but with the
onset of very hot weather, late in June, 1931, the disease reappeared
in the San Joaquin Valley, and heavy losses have also been reported
from the Sacramento Valley and in Ventura County.
Little knowledge is available to indicate how the disease is intro-
duced into a community, how it spreads from farm to farm or from
Cir. 322] An Infectious Brain Disease of Horses and Mules 7
animal to animal on the same farm. The role that flies and other
biting" insects may or may not have in transmitting the disease is
unknown. It is the general belief that the infection is carried by food
or water which has at some time been contaminated by infected animals.
Morbidity. — About one horse in ten in the San Joaquin Valley
showed symptoms in 1930. Approximately 6,000 head developed the
Fig. 8. — Yawning is a frequent symptom.
Fig. 9. — Spasm of the neck muscles twists the head to one side in this stallion.
disease, and about 3,000 of these cases terminated fatally. On one
ranch with 687 horses and mules, 67 contracted encephalomyelitis and
32 died. On certain farms higher proportions than this have occurred,
but it is relatively rare for more than one of a team to show symptoms.
This peculiarity can be explained by the hypothesis that many horses
contract the disease in such a mild form that it is not recognized.
University of California — Experiment Station
RECOMMENDATIONS TO ALL HORSE OWNERS IN INFECTED AREAS
The most hopeful preventive measures consist in the complete
isolation of all horses so far as is practicable. It behooves one to
take into consideration every possible means by which the disease may
be carried from an infected farm to premises where no cases have
existed ; therefore :
Prevent the association of horses from infected areas with those
from noninfected areas.
Do not use water from troughs, 1^1^^^ ditches, buckets, etc.,
which have been used by horses on or from infected premises.
Keep horses away from streams, canals, ditches, and pools. Provide
an abundant supply of fresh well water.
Suspend breeding operations where horses must be moved from
farm to farm. There is a possibility of carrying the disease by moving
animals or materials from one farm to another. Judging by what
occurs in similar but better-known diseases, one is justified in suspect-
ing that apparently normal horses which have been exposed may be
carriers of the virus.
Protect the animals as much as practicable from flies and other
biting insects. In the case of certain very valuable animals, it may
be worth while, during very hot weather, to confine them in darkened
stalls during the day time and use fly sprays liberally. The fact that
few cases have been reported in riding academy horses, polo ponies,
or city dray horses would justify the precaution of temporarily bring-
ing into barns the very valuable animals now at pasture.
A veterinarian in one of the worst-infected sections of California
writes that all cases of encephalomyelitis in his practice had been fed
on the ground. He advised feeding from a rack of some kind and
killing rats, mice, and ground squirrels. He suggested that efforts
be made to stop the transportation of manure from infected districts
to localities where the disease has not as yet been diagnosed.
Cm. 322] An Infectious Brain Disease of Horses and Mules
RECOMMENDATIONS TO OWNERS OF SICK HORSES
Obt&in the services of a \eterinarian as soon as possible. Persons
not accustomed to seeing and working with this malady might mistake
it in the early stages for azoturia, colic, poisoning, heat stroke, or
"staggers" from various other causes.
Keep the sick animals quiet and in the shade. It is imperative that
the animals be kept as quiet as possible. Regardless of how slight the
manifestation of the disease may be, do not work or exercise an
affected animal, as any unnecessary muscular exertion will aggravate
the condition. Should the horse become affected at a great distance
from the barn, it should not be forced to make the trip back — an
Fig. 10. — A good type of supporting frame with a strong rear crossbar and
a feed box high enough to keep the head level with the body.
improvised shade should be erected. Sunlight seems to be of no value
in hastening recovery. Horses and mules allowed to remain in the
direct sunlight during hot weather will only succumb more rapidly.
Protection from Injury. — Care should be exercised to prevent a
sick animal from injuring itself. This may be accomplished by plac-
ing the horse or mule between two timbers held fast by four posts
with wooden braces across each end (see fig. 10). Cross timbers, front
and rear, are necessary because the animal rests by sitting back or
leaning forward. Sacks or padding tied to the timbers will prevent
undue injury to the body. A box should be placed at one end to hold
a water bucket, and a rack should be provided for hay. Chances for
recovery are better if the animal can be kept standing. This may be
accomplished by the use of canvas or wide belting passed under the
abdomen and chest and attached to the side bars.
10
University of California — Experiment Station
Support by an abdominal sling, as shown in figure 11, may be
preferable in very severe cases. This should be used in conjunction
with the side and cross bars, and not as shown in figure 12, so that
Fig. 11. — The combined use of a sling and supporting frame is desirable
in severe cases.
Fig. 12. — -The use of a sling without any supporting frame is valueless in
severe cases such as this.
during periods of collapse support will be furnished for the head
and rump.
Some veterinarians prefer to omit the supporting devices and place
the animal in a large box stall. It should be very well bedded with
Cm. 322] An Infectious Brain Disease of Horses and Mules
11
straw, however, and if the animal gets down an effort should be made
to keep it in the breast position shown in figure 14. Bales of hay and
sacks stuffed with straw are useful in doing this. If left- to lie flat on
>*Asp*£*-'-Wr
Fig. 13. — Animal lying flat on its side without any protection from the
ground. Do not permit this when possible to get it to stand or assume a breast
position.
Fig. 14. — Assisting an animal to assume a breast position.
its side, the body and head soon become seriously bruised from con-
tact with the ground (fig. 13). Two or three times a day the animal
should be assisted to its feet, A veterinarian who treated about 75
12 University of California — Experiment Station
cases during" July, 1931, writes: "The horses that were able to get up
on their feet occasionally during the first four days of the sickness
all got well."
Animals that are unable to rise should be turned over at four or
five-hour intervals to avoid congestion of the blood in the lower part
of the body. This will also tend to prevent "bedsores," pneumonia,
and other complications which quickly develop if a horse lies for a
long time on one side.
Feed, — Small amounts of wholesome food, such as freshly-cut
alfalfa or cured alfalfa, or, if neither is available, good grain hay, will
materially help in sustaining the strength of the affected horse. In
mild cases, the appetite usually remains normal and many horses badly
affected will consume some food if it is placed before them. They
often nibble hay from the rack or ground as the disease progresses.
Feeding will take place only when the sick animal can secure food with
little or no effort. Some of the animals refuse food for a few days, but,
as recovery sets in, the appetite returns to normal and should be
satisfied with the best quality of feed obtainable.
Water. — Thirst is one of the most common symptoms, and it is
generally believed by veterinarians that the animals should be per-
mitted to drink as often and as much as they wish.
Studies at the University of California have shown that, in
advanced cases, there is a marked dehydration of the blood and tissues.
This indicates that sick horses should be induced to drink as frequently
as practicable. Those that are able to swallow usually drink eagerly
and should have constant access to a good, clean water supply. They
should not be made to drink from containers on the ground as they
will have difficulty in keeping their balance while lowering the head.
In some cases, there is a semiparalysis of the lips, tongue, and pharyn-
geal muscles. Such animals will often dip the muzzle in water but
apparently make no attempt to drink. If water is slowly injected into
the mouth (fig. 15), they generally swallow willingly. Time and
patience will be necessary in cases that have difficulty in drinking.
Care should be taken not to raise the mouth and nose too high nor to
attempt to force water or other liquids down the throat.
Avoid drenching. Attempts by forced drenching to administer oils,
salts, and other drugs to animals affected with encephalomyelitis are
very apt to result disastrously. The horse may be in a state of stupor
or collapse, or it may be excited. Either of these conditions is asso-
ciated with difficulty in swallowing. Elevating the head, as is usually
done in drenching, may cause the fluid to pass down the trachea or
Cm. 322] An Infectious Brain Disease of Horses and Mules 13
windpipe into the lungs, which, in turn, in these cases almost invariably
produces a mechanical pneumonia.
The safest way to introduce liquids into the stomach of a horse or
mule is by the use of a stomach tube. On account of the difficulty of
passing the tube through the mouth of these animals, it is usually
passed via a nostril. This operation should be done by a veterinarian.
In certain cases the use of the stomach tube has been found to be
injurious because its passage has induced pneumonia from inhalation
into the lungs of putrid saliva collected in the throat. Rectal injec-
. „ -
> ^^V^'N*
Fig. 15. — Assisting a thirsty animal to drink. A short piece of metal pipe is
inserted a few inches into the mouth. To prevent choking do not insert the
pipe too far nor raise the head too high.
tions may be helpful but should be given only on a veterinarian's
advice.
Do not experiment with drugs not prescribed or recommended by
a veterinarian. The chances of recovery will probably be lessened by
such dosing. Even if the drugs should be harmless, the unnecessary
disturbance and irritation in giving them to the animal may reduce
the chance of recovery. The sick animal should be kept as quiet and
undisturbed as possible.
Each case requires special, individual treatment. No specific treat-
ment generally applicable to all cases has yet been found. The most
successful veterinarians depend on conservative efforts to alleviate the
symptoms. University veterinarians, in cooperation with various
14 University of California — Experiment Station
veterinary practitioners, have tried a number of chemicals and serums,
but as yet nothing' has been found of special value in neutralizing or
reducing the effects of the virus which is the primary cause of the
disease.
Experiments with the virus under controlled conditions are being
actively carried on at the University of California. Any results of
practical value will be immediately made public.
STATION PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION
BULLETINS
No.
253. Irrigation and Soil Conditions in the
Sierra Nevada Foothills, California.
263. Size Grades for Ripe Olives.
277. Sudan Grass.
279. Irrigation of Rice in California.
283. The Olive Insects of California.
304. A Study of the Effects of Freezes on
Citrus in California.
310. Plum Pollination.
331. Phylloxera-resistant Stocks.
335. Cocoanut Meal as a Feed for Dairy
Cows and Other Livestock.
343. Cheese Pests and Their Control.
344. Cold Storage as an Aid to the Market-
ing of Plums, a Progress Report.
347. The Control of Red Spiders in Decid-
uous Orchards.
348. Pruning Young Olive Trees.
349. A Study of Sidedraft and Tractor
Hitches.
357. A Self-Mixing Dusting Machine for
Applying Dry Insecticides and Fun-
gicides.
361. Preliminary Yield Tables for Second-
Growth Redwood.
362. Dust and the Tractor Engine.
363. The Pruning of Citrus Trees in Cali-
fornia.
364. Fungicidal Dusts for the Control of
Bunt.
366. Turkish Tobacco Culture, Curing, and
Marketing.
368. Bacterial Decomposition of Olives
During Pickling.
369. Comparison of Woods for Butter Boxes.
370. Factors Influencing the Development
of Internal Browning of the Yellow
Newtown Apple.
371. The Relative Cost of Yarding Small
and Large Timber.
373. Pear Pollination.
374. A Survey of Orchard Practices
Citrus Industry of Southern
fornia.
379. Walnut Culture in California.
386. Pruning Bearing Deciduous
Trees.
388. The Principles and Practice of
Drying Fruit.
389. Berseem or Egyptian Clover.
390. Harvesting and Packing Grapes in
California.
391. Machines for Coating Seed Wheat with
Copper Carbonate Dust.
392. Fruit Juice Concentrates.
393. Crop Sequences at Davis.
394. I. Cereal Hay Production in California.
II. Feeding Trials with Cereal Hays.
396. The Mat Bean, Phaseolus Aconitifolius.
404. The Dehydration of Prunes.
405. Citrus Culture in Central California.
406. Stationary Spray Plants in California.
407. Yield, Stand, and Volume Tables for
White Fir in the California Pine
Region.
408. Alternaria Rot of Lemons.
409. The Digestibility of Certain Fruit By-
products as Determined for Rumi-
nants. Part I. Dried Orange Pulp
and Raisin Pulp.
410. Factors Influencing the Quality of Fresh
Asparagus After it is Harvested.
412. A Study of the Relative Value of Cer-
tain Root Crops and Salmon Oil as
Sources of Vitamin A for Poultry.
414. Planting and Thinning Distances for
Deciduous Fruit Trees.
in the
Cali-
Fruit
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415.
416.
418.
419.
420.
421.
423.
425.
426.
427.
428.
431.
432.
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436.
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447.
448.
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450.
451.
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456.
458.
459.
460.
462.
464,
465.
The Tractor on California Farms.
Culture of the Oriental Persimmon in
California.
A Study of Various Rations for Fin-
ishing Range Calves as Baby Beeves.
Economic Aspects of the Cantaloupe
Industry.
Rice and Rice By-Products as Feeds
for Fattening Swine.
Beef Cattle Feeding Trials, 1921-24.
Apricots (Series on California Crops
and Prices).
Apple Growing in California.
Apple Pollination Studies in California.
The Value of Orange Pulp for Milk
Production.
The Relation of Maturity of California
Plums to Shipping and Dessert
Quality.
Raisin By-Products and Bean Screen-
ings as Feeds for Fattening Lambs.
Some Economic Problems Involved in
the Pooling of Fruit.
Power Requirements of Electrically
Driven Dairy Manufacturing Equip-
ment.
Investigations on the Use of Fruits in
Ice Cream and Ices.
The Problem of Securing Closer Rela-
tionship between Agricultural Devel-
opment and Irrigation Construction.
I. The Kadota Fig. II. The Kadota
Fig Products.
Grafting Affinities with Special Refer-
ence to Plums.
The Digestibility of Certain Fruit By-
Products as Determined for Rumi-
nants. Part II. Dried Pineapple
Pulp, Dried Lemon Pulp, and Dried
Olive Pulp.
The Feeding Value of Raisins and
Dairy By-Produces for Growing and
Fattening Swine.
Beans (Series on California Crops and
Prices).
Economic Aspects of the Apple In-
dustry.
The Asparagus Industry in California.
A Method of Determining the Clean
Weights of Individual Fleeces of Wool.
Farmers' Purchase Agreement for Deep
Well Pumps.
Economic Aspects of the Watermelon
Industry.
Irrigation Investigations with Field
Crops at Davis, and at Delhi, Cali-
fornia, 1909-1925.
Studies Preliminary to the Establish-
ment of a Series of Fertilizer Trials
in a Bearing Citrus Grove.
Economic Aspects of the Pear Industry.
Rice Experiments in Sacramento Val-
ley, 1922-1927.
Reclamation of the Fresno Type of
Black-Alkali Soil.
Yield, Stand and Volume Tables for
Red Fir in California.
Factors Influencing Percentage Calf
Crop in Range Herds.
Economic Aspects of the Fresh Plum
Industry.
Lemons (Series on California Crops
and Prices).
Prune Supply and Price Situation.
Drainage in the Sacramento Valley
Rice Fields.
Curly Top Symptoms of the Sugar Beet.
BULLETINS— (Continued)
No. No,
466. The Continuous Can Washer for Dairy 484.
Plants.
467. Oat Varieties in California. 485.
468. Sterilization of Dairy Utensils with 486.
Humidified Hot Air.
469. The Solar Heater. 487.
470. Maturity Standards for Harvesting
Bartlett Pears for Eastern Shipment. 488.
471. The Use of Sulfur Dioxide in Shipping
Grapes. 489.
472. Adobe Construction.
473. Economic Aspects of the Sheep In-
dustry.
474. Factors Affecting the Cost of Tractor 490.
Logging in the California Pine
Region. 491.
475. Walnut Supply and Price Situation.
477. Improved Methods of Harvesting Grain 492.
Sorghum. 493.
478. Feeding and Management of Dairy 494.
Calves in California. 495.
479. I. Irrigation Experiments with Peaches
in California. II. Canning Quality 496.
of Irrigated Peaches.
480. The Use, Value, and Cost of Credit in
Agriculture. 497.
481. Utilization of Wild Oat Hay for Fat-
tening Yearling Steers. 498.
482. Substitutes for Wooden Breakpins. 500.
483. Utilization of Surplus Prunes.
The Effects of Desiccating Winds on
Citrus Trees.
Drying Cut Fruits.
Pullorum Disease (Bacillary White
Diarrhea of Chickens).
Asparagus (Series on California Crops
and Prices).
Cherries (Series on California Crops
and Prices).
Irrigation Water Requirement St\idies
of Citrus and Avocado Trees in San
Diego County, California, 1926 and
1927.
Olive Thinning and Other Means of
Increasing Size of Olives.
Yield, Stand, and Volume Tables for
Douglas Fir in California.
Berry Thinning of Grapes.
Fruit Markets in Eastern Asia.
Infectious Bronchitis in Fowls.
Milk Cooling on California Dairy
Farms.
Precooling of Fresh Fruits and Tem-
peratures of Refrigerator Cars and
Warehouse Rooms.
A Study of the Shipment of Fresh
Fruits and Vegetables to the Far East.
Pickling Green Olives.
Dehydration of Grapes.
No.
117. The Selection and Cost of a Small
Pumping Plant.
127. House Fumigation.
178. The Packing of Apples in California.
203. Peat as a Manure Substitute.
212. Salvaging Rain-Damaged Prunes.
230. Testing Milk, Cream, and Skim Milk
for Butterfat.
232. Harvesting and Handling California
Cherries for Eastern Shipment.
239. Harvesting and Handling Apricots and
Plums for Eastern Shipment.
240. Harvesting and Handling California
Pears for Eastern Shipment.
241. Harvesting and Handling California
Peaches for Eastern Shipment.
243. Marmalade Juice and Jelly Juice from
Citrus Fruits.
244. Central Wire Bracing for Fruit Trees.
245. Vine Pruning Systems.
248. Some Common Errors in Vine Pruning
and Their Remedies.
249. Replacing Missing Vines.
250. Measurement of Irrigation Water on
the Farm.
253. Vineyard Plans.
255. Leguminous Plants as Organic Ferti-
lizers in California Agriculture.
257. The Small-Seeded Horse Bean (Vicia
faba var. minor).
258. Thinning Deciduous Fruits.
259. Pear By-Products.
261. Sewing Grain Sacks.
262. Cabbage Production in California.
263. Tomato Production in California.
265. Plant Disease and Pest Control.
266. Analyzing the Citrus Orchard by Means
of Simple Tree Records.
CIRCULARS
No.
269.
270.
273.
276.
278.
279.
282.
287.
288.
290.
294.
295.
296.
301.
302.
304.
307.
308.
310.
311.
312.
313.
316.
317.
318.
319.
320.
An Orchard Brush Burner.
A Farm Septic Tank.
Saving the Gophered Citrus Tree.
Home Canning.
Olive Pickling in Mediterranean
Countries.
The Preparation and Refining of Olive
Oil in Southern Europe.
Prevention of Insect Attack on Stored
Grain.
Potato Production in California.
Phylloxera Resistant Vineyards.
The Tangier Pea.
Propagation of Deciduous Fruits.
Growing Head Lettuce in California.
Control of the California Ground
Squirrel.
Buckeye Poisoning of the Honey Bee.
The Sugar Beet in California.
Drainage on the Farm.
American Foulbrood and Its Control.
Cantaloupe Production in California.
The Operation of the Bacteriological
Laboratory for Dairy Plants.
The Improvement of Quality in Figs.
Principles Governing the Choice, Oper-
ation, and Care of Small Irrigation
Pumping Plants.
Fruit Juices and Fruit Juice Beverages.
Electrical Statistics for California
Farms.
Fertilizer Problems and Analysis of
Soils in California.
Termites and Termite Damage.
Pasteurizing* Milk for Calf Feeding.
Preservation of Fruits and Vegetables
by Freezing Storage.
16m-8,'31