6 BULLETIN 167, U. S. DEPARTMENT OF AGRICULTURE. 
Glover and Robbins, 1915, page 25, speak of the subject as follows: 
Scrub oak is considered poisonous by many:stockmen. They will take the pains 
to keep their stock from the oak thicket. Itis very likely that most cases of poisoning 
resulting from cattle grazing in scrub-oak thickets are due to larkspur which grows 
therein. 
The foregoing covers all the literature that has been found on the 
subject of poisoning by oak leaves. It may be noted that the bibliog- — 
raphy is surprisingly small, and that even the somewhat extended 
account of Cornevin contains much theoretical matter and is not 
supported by experimental evidence. 
POISONING BY OAK LEAVES IN NORTH AMERICA. 
Throughout the grazing region of the West there is a very general 
belief in the poisonous properties of oak leaves, more particularly 
with regard to their supposed toxic properties for cattle. Heavy 
losses are said to have been caused in certain localities, and many 
inquiries have been addressed to the Department of Agriculture for 
information concerning the disease and its treatment. In connec- 
tion with the investigations of poisonous plants and their effects 
there has been an attempt to collect all available information on | 
the subject, and feeding experiments have been carried on during 
four summers. 
As has already been indicated, the published statements with 
regard to poisoning by oak leaves in America are very few. The 
Department of Agriculture, however, has received by correspondence 
considerable information on the subject which may be summarized 
as follows: 
Localities of supposed poisoning.—The States from which most of 
the complaints have come are Colorado, Utah, New Mexico, and 
Texas. Many of the reports have come through forest supervisors, 
the following national forests bemg represented: San Isabel, Las 
Animas, Nebo, Fillmore, La Sal, Wasatch, Manti, and Fishlake. It 
may be noted that the Utah national forests are largely represented, 
and more detailed complaints have come from that State than from 
the others. 
Species supposed to be poisonous.—Of course, the reports ordinarily 
do not connect the disease with any one species. It is evident, 
however, from our knowledge of the local flora in the places from which 
the complaints come, that most of the trouble is ascribed to two 
species, Quercus gambellii Nutt. and Q. havardi Ryd. The latter 
species 1s popularly known in Texas and New Mexico as the ‘‘shin- 
nery’’ oak, and the plant is said to ‘‘shinnery”’ cattle. 
Season when poisoning occurs.—While many of the reports are 
indefinite as to whether poisoning is more likely to occur at particular 
seasons of the year, there is a general agreement that most cases 
