284 REPORT OF OFFICE OF EXPERIMENT STATIONS. 



A woll-kopt private herd of 102 cows was also cx-aminod. Hero 

 also Icufocytes ucro invarial)ly present in the milk, the raii<;e heing 

 from 2,000 to 4, (»0( ).()()() per ciihie centimeter. These and other ob- 

 *servations, recorded in the bulletin cited, made with cows, nearly all 

 of which at least were un(iuestionably in a state of perfect health, 

 show quite conclusively that leucocytes are re^rularly present in cows' 

 milk, that with most cows their numbers run into the thousands per 

 cubic centimeter, and that variations within wide limits signify 

 nothing. 



It was observed, nevertheless, that the milk of cows affected with 

 garget always showed a high leucocyte count, and in studying such 

 milk Doane observed certain threads which reseml)led similar threads 

 found in pus. These were best stained with Delafield's hematoxylin 

 modified by the addition of 15 per cent of carbolic acid and coimter 

 staining with eosin. When these threads were present in any con- 

 siderable quantity in milk large numbers of leucocytes were found 

 collected in masses or clumps. In milk showing a low leucocyte 

 count no such masses of leucocytes and fibrin threads were found. 

 In milk showing a high leucocyte count the clumps were often pres- 

 ent. In practice, therefore, a high leucoc^'te count would render a 

 sample of milk suspicious and the presence of fibrin in addition, as 

 indicated by clumping of the leucocytes, or as demonstrated by stain- 

 ing of the threads, woidd, in the opinion of Doane, furnish satis- 

 factory proof of the presence of inflammation in the udder, and in 

 such cases the milk must be considered unfit for use. Results of 

 trials of this method in actual milk inspection are yet wanting. 



Estrum, or heat, while not a disease of cows, has been studied as 

 regards its possible effect upon the character of the milk, Doane 

 has reported observations on this subject." Determinations of the 

 total solids, fat, i:»rotein, casein, and sugar in the milk of five cows 

 before, during, and after periods of heat failed to show any marked 

 variations in these constituents. It was, however, considered possible 

 that the milk might be abnormal in other respects than that indicated 

 by chemical analvsis. 



The stage of lactation exerts some influence upon the composition 

 of the milk, and the extensive dairy herd records at the experiment 

 stations are valuable in studying this question. 



Dehorning, excitement, exposure to storms, and other influences 

 have been reported by numerous stations as affecting temporarily the 

 yield and composition of the milk of cows, but no mention has been 

 made that any such factors affect the wholesomeness of the product. 



The observation was made by Beach ancf Clark ^ that in tests of a 



a Maryland Sta. Bui. 9.5. 



6 Connecticut Storrs Sta. Bui. 32, p. 10. 



