New York Agricultural Experiment Station. 171 



The comparison of the experimental animals with their controls 

 may be started with a discussion of Gerty F. 2 (experimental 

 animal) with Hammond F. 1 (control). These two animals were 

 the most satisfactory in that they both gave milk having a fairly 

 constant cell content and were not so near the end of their period 

 of lactation as the other animals. Gerty F. 2 was in the seventh 

 and eighth month of her period of lactation at the time and gave 

 an almost constant amount of milk. The cell content of her milk 

 showed a slight average decrease after the first week with no marked 

 fluctuations (see Table XIV and Graph IV, upper portion). Ham- 

 mond F. 1, her control, had calved three weeks later than Gerty F. 2, 

 and gave a gradually decreasing amount of milk. The cell content 

 of her milk was constantly somewhat higher and more fluctuating 

 than that of Gerty F. 2. 



A comparison between Ruth F. (experimental animal) with Gerty 

 F. 1 (control) shows that Ruth F. gave a gradually decreasing amount 

 of milk while Gerty F. 1 maintained a practically constant amount 

 to the end of the experiment (see Table XIV and Graph IV, lower 

 portion). This was to have been expected as Ruth F. was within 

 one month of the end of her period of lactation while Gerty F. 1 

 was milked for two and one-half months longer. Ruth F. gave milk 

 which contained a gradually increasing number of cells but the per- 

 centage of increase was not great nor were the fluctuations as many 

 nor as great as in her control animal. Gerty F. 1, the control, showed 

 a marked increase in the number of cells in her milk toward the end 

 of the experiment and in several instances gave milk containing 

 over 1,000,000 cells per cubic centimeter. 



None of these four animals showed any abnormal condition of 

 milk or of health at any time during the experiment nor for months 

 thereafter. Ruth F. suffered from milk fever at her next calving 

 period and Gerty F. 1 had a skin disease during the following summer, 

 but these conditions cannot be connected in any way with the experi- 

 ments here outlined. 



Millie D. (experimental animal) and Mabel S. F. (control) both 

 proved to be animals which were not entirely normal in every respect 

 and, therefore, in one way, not so satisfactory for the purposes of 

 this experiment but on account of their abnormality, more interest- 

 ing for study than the other animals. Millie D. was in the ninth 

 and tenth month of her period of lactation but had only just become 



