A MONOGRAPH ON TREMBLES, OR MILKSICKNESS, AND 
WHITE SNAKEROOT.* 
By 
F. A. Wolf, Plant Pathologist. 
R. S. Curtis, Animal Husbandman, Office Beef Cattle and She,ep Investigations, 
Animal Industry Division. 
B. F. Kaupp, Poultry Investigations and Pathology, Animal Industry Division. 
Introduction 
For a number of years, complaints have come to this Station through 
letters from farmers, county agents, and extension workers, of the 
occurrence within the mountainous sections of North Carolina of a 
peculiar malady known as Trembles. This disease annually causes 
very considerable losses of horses, cattle, sheep, and hogs. Further¬ 
more, in sections where this disorder is present, the belief is unani¬ 
mously and firmly held that man may contract the disease by the 
ingestion of milk, hence the name “milksickness” which physicians 
employ, of certain milk products and of flesh of animals affected with 
trembles. 
A questionnaire was therefore sent out to learn, among other things, 
something of the distribution of trembles, the seasonal incidence of the 
disease, the kinds of animals affected, preventive and curative measures 
employed, losses, and opinions as to the cause. It was found from 
these reports that the disease very probably occurs in the mountainous 
portions of all the counties in western North Carolina and in the imme¬ 
diately adjacent sections of States having similar conditions. The 
losses, furthermore, to the live-stock interests are so grave, since the 
danger of an outbreak is ever present and since so few affected animals 
recover, except when cases are discovered and treated in the incipient 
stages, that the farmer is reluctant to make any considerable invest¬ 
ment in stock in sections where the malady is likely to occur. 
Not only is an additional risk placed upon live-stock production by 
the presence of this disease, but it also discourages certain industries 
such as creameries and cheese factories whose success depends upon a 
lively interest in the growing of domestic animals. The popular atti¬ 
tude toward the disease is typified by the report of one county agent, 
who asserts that in his section trembles is the limiting factor in the 
establishment of cheese factories. 
*The authors hereby gratefully acknowledge the hearty cooperation of Director B. W. Kil¬ 
gore and Mr. Dan T. Gray in providing ways and means for conducting this investigation. 
Furthermore, appreciation is, by this means, expressed for the several services rendered by 
our colleagues Mr. Earl Hostetler, Mr. George Evans, Mr. L. I. Case, Mr. A. L. Jerdan, Mr. 
F. T. Peden, Mr. W. R. Radford, Dr. J. I. Handley, Dr. L. F. Koonce, and Mr. A. C. Foster. 
Thanks are also due Mr. E. D. Bowditch, formerly Demonstration Agent of Clay County, from 
whom the white snakeroot was procured, Mr. M. R. Penland, for daily shipments of the weed, 
and Mr. E. McPhaul for much of the labor in connection with feeding experiments and the 
keeping of records. 
