16 MASS. EXPERIMENT STATION BULLETIN 436 



still apparent. Individual cows, even within a breed, varied widely in their 

 response to the hormone stimulus. Holstein cows in general were less responsive 

 than Ayrshires, Guernseys, or Jerseys. Live weight decreased sharply at first, 

 but after a few weeks increased slowly, even while the hormone was still being 

 fed. Respiration and pulse rates in general were accelerated somewhat, but 

 individual animals showed great variations in these respects. 



The Effect of Massive Doses of Irradiated Yeast on Incidence of Milk Fever 

 in Dairy Cows. (J. G. Archibald.) This project is a part of a more comprehen- 

 sive one, the other phases of which were terminated several years ago. This par- 

 ticular phase has been kept active but data have been slow in accumulating 

 because of the limited number of cows (6) in the college herd suitable for the 

 study; that is, having a previous history of milk fever. 



The procedure consists in feeding one million units of vitamin D in irradiated 

 yeast daily per cow for one month previous to calving. As indicated above the 

 yeast was fed only to cows having had milk fever previously. In five out of the 

 six cases, cows receiving irradiated yeast did not develop milk fever; also, when 

 used as controls in a subsequent lactation (that is, not fed the yeast), two out of 

 three of these cows did have milk fever again. A fourth cow, not intended as a 

 control but refusing the grain with which the yeast was mixed, makes it three 

 out of four cases in this latter category. Especially worthy of note is the case 

 of one cow which responded to the yeast feeding in two successive lactations, but 

 reverted to her original status when used later as a control. 



Further cases will be studied before final conclusions are drawn; but so far as 

 these cows are concerned, the treatment appears to have been a definite value. 



DEPARTMENT OF BACTERIOLOGY 

 Leon A. Bradley in Charge 



Bacteriological Studies of Rural Water Supplies. (James E. Fuller.) This 

 study was a comparative dilTerentiation of coliform bacteria from privately 

 owned rural water supplies at several temperatures: 37° C., as provided by the 

 Standard Methods of Water Analysis of the American Public Health Associa- 

 tion; 44°C., as employed by the British practice; and 46° C., as employed in 

 the Eijkman test. To provide an intermediate temperature between A.P.H.A. 

 Standard Methods and the British system, 40° C. was also employed in the study. 

 The tests employed were the indole, methyl-red, Voges-Proskauer, and sodium 

 citrate tests, as directed in the A.P.H.A. Standard Methods. The results warrant 

 the recommendation that the methyl-red test at 44° C. be employed for effective 

 differentiation of sewage-type (fecal) coliform bacteria from surface-wash (soil- 

 type) coliform bacteria in the testing of raw waters from wells, springs, and 

 streams. The study has been completed and results published.^ 



Relation of Chloramine-resistant Bacteria to Milk Supplies. (James E. 

 Fuller.) The isolation and study of bacteria surviving chloramine treatment in a 

 public Wcter supply have been reported and published. ^ Since the supply in 

 question, the others like it, serve milk-bottling plants and some dairy farms, it 

 appeared to be desirable to determine the effect of these bacteria on milk sup- 

 plies. Results indicate that all of the bacterial cultures isolated were capable of 



'journal of Bacteriology, Vo. 51, No. 4, pp. 457-464, April 1946. 



'Journal New England Water Works Association, Vol. 58, No. 2, pp. 89-100, June 1944; and 

 Vol. 59, No. 3, pp. 244-251, September 1945. 



