496 Trans. Acad. Sci. of St. Louis. 



demonstrated that they were composed of minute, rather stiff 

 hairs, seldom more that one-tenth of an inch in length, pointed 

 at one end, and covered with fine barbules directed toward 

 the pointed apex, which usually faced the surface of the ball. 

 Further investigation showed that these hairs were derived 

 from the calyx of the crimson clover, the assumption being 

 that the horses had fed upon over-ripe plants of this species 

 (Trifolium incarnatum), the hairs which accumulated in the 

 stomach being aggregated into spherical felted balls in the 

 manner assumed for the above-described Mexican specimens 

 composed of Opuntia hairs. 



In discussing the use of oat bran as a food for domestic 

 animals, especially horses and donkeys, Dr. Harz* character- 

 rizes it as a dangerous food material, because it favors the 

 formation of large bezoars, which he had previously discussed 

 in an extensive paper, f in which is given a classification of 

 structures of this kind, with a very considerable citation 

 of earlier literature. 



It is a frequent practice in Texas to cut the branches of 

 cacti which are fed to stock into half -inch lengths. In this 

 way, every one of the obliquely set longer spines of Opuntia 

 Engelmanni (and of some other species which are so used) is 

 almost certain to be cut off, so that the danger from the spines 

 is removed. This treatment, however, does not destroy the 

 barbed hairs of the pulvini, of which the bezoars under con- 

 sideration are composed. It is also the practice, in some 

 places, to roast the fragments as a means of completely re- 

 moving the spines and barbed hairs, but this is objected to 

 by some feeders, because the roasting has been asserted to 

 add to the laxative properties of the cactus. % Where some 

 such treatment has not been resorted to, injury to the animals 

 not infrequently results; and in the bulletin referred to, 

 Dr. Vasey gives a number of instances in which cattle have 



* Landwirtschaftliche Samenkunde, ii. 1315. 



t Beitrage zur Kenntniss der PflanzeDbezoare des Pferdes und Rindes. 

 Deutsche Zeitschrift fur Thiermedicin und vergleichende Pathologie, i. 393- 

 407. 1875. 



% Vasey, Grasses of the South. U. S. Dept. of Agriculture, Botanical 

 Division, Bulletin No. 3, 52. 1887. 



