272 EXPERIMENT STATION RECORD. [Vol 3T 



It is noted that the average annual milk production per cow increased from 

 5,300.9 lbs. in 1911 to 5,721.2 lbs. in 1915. During this time the average fat con- 

 tent of the milli increased from 4.27 to 4.9 per cent, and the annual milli-fat 

 production per cow from 226.6 to 279.8 lbs. 



Studies in milk secretion, I, II, J. Hammond and J. C. Hawk {Jour. Agr. 

 Set. [England], 8 (1917), No. 2, pp. 139-15S, figs. 2).— Two articles are pre- 

 sented. 



I. The effect of nutrition on yield and composition (pp. 139-146). — Using 

 well-fed goats, a study was made of changes in the yield and composition of 

 the milk which followed a sudden change in nutrition. The changes in nutri- 

 tion were brought about by the administration of phlorizin, together with the 

 control of the food supply. 



When food was withheld from goats for a short time and then an abundant 

 supply given tliem, the amount of milk and fat secreted was decreased and 

 the percentage of fat increa.sed, due to the lowering of the plane of nutrition. 

 When food was withheld, phlorizin injected, and a few days afterwards a 

 plentiful supply of food given, results similar to those above, yet much more 

 marked, were secured. The return to normal production was very gradual, 

 indicating that phlorizin has a rather long-continued action. In two cases out 

 of the three, the fat percentages at tlie end of the experiment was below that 

 at the beginning, although the milk yield had not returned to normal. In a 

 third series of experiments phlorizin was Injected into goats under normal 

 conditions of feeding. There was great variation in the effects on different 

 Individuals, the results Indicating that it was the goats in the poorest state of 

 nutrition that showed a diminution In milk yield qs a result of the injection of 

 phlorizin. 



II. The relation of the glands of internal secretion to milk production (pp. 

 147-153). — The effect of pituitary extract on the milk flow of animals under 

 conditions of reduced nutrition was studied. Goats were injected with 1 cc. 

 of pituitary extract per head dally dnrlng a period of sudden change from a 

 high to a low condition of nutrition. This change was brought about by with- 

 holding food or by the injection of phlorizin as in the experiments noted above. 



The results indicate that the amount of milk produced by the action of 

 pituitary extract varies with the .'^tate of nutrition. It was found that the 

 variation in yield as a result of pituitary injections was not so great as the 

 normal daily variations. The percentage of fat in the milk produced within 

 half an hour after the Injection of pituitary extract rises with the fall in 

 nutrition, as it does in the case of normal milk. 



A study was made of the ifToct of the injection of adrenalin into lactating 

 goats. In these tests an average of 6 cc. of a 1:1,(XH) solution of adrenalin 

 chlorid was injected into each goat on alternate days after the morning milking, 

 the goats being milked again after an interval of half an hour. On the other 

 days sterilized water was injected in place of the adrenalin. The Injection of 

 the adrenalin had no immediate effix-t on the amount of milk secreted, but there 

 was a secondary effect causing a decrease in the amount of milk produced for 

 n day following the injection. The percentage of fat in the milk was increased, 

 but the amount of fat was somewhat decreased following the injection of 

 adrenalin. 



The results of these experiments indicate that the rate of milk flow Is very 

 susceptible to changes In the sugar metabolism of the animal. 



On the fat of Egyptian buffalo milk, G. Hooam and E. Griftit«s- Jones 

 (Dcpt. Pub. Health [Epuiit], Hyg. Inst. Pub. 5 (iP/6), pp. 5).— Analyses are 

 given of 69 samples of buffalo milk fat, each sample being representative of the 

 mixed milk of a complete milking of five or six buffaloes. 



