Composition and function of colostrum and regression milk.

Abstract

WE have been interested for some years in the similarities which exist between the composition of colostrum and ‘regression’ milk. By the latter term is meant the fluid which can be expressed from the mammary gland during its involution. Our attention was directed to these resemblances by a study of the cholinesterase in bitch's milk1, and some estimations were accordingly made of the activities of other enzymes. It was not proposed to publish anything on the subject until further investigations had been made; but the appearance of Campbell, Porter and Petersen's communication in Nature2 describing the accumulations of plasma cells in the bovine gland at the beginning of lactation and at the experimental close of milking, and their probable role in antibody production, has prompted us to place the results of our preliminary investigations on record at the present time in case they may be of value to others working on the subject.