UNITED STATES DEPARTMENT OF AGRICULTURE 
J^^I^j-u 
BULLETIN No. 767 
Contribution from the Bureau of Animal Industry 
JOHN R. MOHLER, Chief. 
jrwiP"^w'«. 
Washington, D. C. 
PROFESSIONAL PAPER 
April 28, 1919 
OAK-LEAF POISONING OF DOMESTIC ANIMALS, 
By 0. Dwight Marsh, Physiologist in Charge of Poisonous-Plant Investigations, A. B. 
Clawson, Physiologist, and Hadleigh Marsh, Veterinary Inspector, Bureau of 
Animal Industry. 
CONTENTS. 
Page. 
Historical summary and review of literature . . 1 
Poisoning by oak leaves in North America... 6 
Experimental work with scrub oak 7 
Experimental work with " shinncry " oak. . . 21 
General results of the experimental work 30 
Symptoms 30 
Autopsy findings 31 
Microscopic pathology 32 
Length of time necessary to produce 
harm from oak brush 32 
Effect of eating oak with other feeds 33 
Page. 
General results of experimental work— Con- 
tinued. 
Active principle or principles causing 
oak-brush poisoning 33 
Summary of conclusions from experimental 
work 34 
Discussion of results with relation to previous 
investigations 35 
Practical considerations for range grazing 35 
Literature cited 36 
HISTORICAL SUMMARY AND REVIEW OF LITERATURE. 
Although the literature on poisoning by acorns is extensive, publi- 
cations on poisoning by oak leaves are comparatively few. The 
earliest recorded statement regarding the injurious properties of oak 
leaves is by Mascal, 1662, page 243/ who says " Again oak leaves, if 
sheep eat thereof green, it is evil for them, especially for young lambs, 
which will kill them; and likewise of other cattel." 
Apparently there was no other reference to this subject until 1893, 
when Cornevin treats of it quite fully. As this is the only extended 
account in the literature and as his work i$ not common in libraries, 
his statement is quoted in full (by translation) as follows : 
There are no less than 300 species of the genus Quercus. For our purpose we con- 
sider only one, the most common. Moreover what is said about this will apply to the 
others. 
Quercus robur, L. (Chene rouvre). — According to many botanists we should unite 
under this Linnean species the two varieties Q. pedunculata Thrh. and Q. sessiflora 
Smith as well as the forms derived from them, especially Q. Cerris and Q. pubescens 
Wills. 
1 For complete titles of works cited sec list of literature on page 36. 
99620°— 19— Bull. 767 1 
