1906.] 



Trifolium Incarnatum. 



269 



be imagined, as it contained 172 florets similar to the one 

 depicted. 



On several occasions during recent years the writer has had 

 occasion to examine microscopically hair balls removed from 

 the intestines of sheep and horses, which have, by causing an 

 obstruction, been the cause of death. 



In appearance the hair ball has the look of a lump of 

 smooth dried clay, but, on handling it, its extreme lightness is 

 noticeable, and, when closely examined, it has been found to 



J 



Fig. 7. — Geranium Molle (without husk) (magnified five diameters). 



Fig. 8. — Field Madder (magnified five diameters). 



be composed of minute hairs. These hairs, when teased out 

 and put under the microscope, proved to be identical with 

 the hair of the mature flower-head of the Trifolium. These hairs 

 are serrated or barbed (see Fig. 2), and in consequence of the 

 movement of the food in the stomach, become felted and form 

 balls. 



In this connection the result of an inquiry made on behalf of 

 the United States Government into the death of several horses 

 is of interest. The report says : — " When the hair balls have 

 once developed to such a size that they cannot pass through 

 the intestines no practical remedy can be suggested, but 



