SO-CALLED 'BIOLOGICAL PROPERTIES' OF MILK 123 



present in the milk. They found further that if the calf was allowed 

 to suckle an immunised mother, beginning at the fifth day after 

 birth, only about T0 foj- of the total amount of antitoxin present in 

 the milk was absorbed. 



Almost identical results were obtained by Much and Happich 

 in a case of a woman who had received tetanus antitoxin on the 

 day before, and four days after, the confinement. The blood of the 

 infant born the day after the first injection contained no antitoxin. 

 The amount of antitoxin present in the milk was estimated and 

 the amount which subsequently appeared in the infant's blood. 

 It was found that in the first four days after birth the child had 

 absorbed by suckling about of the total amount of antitoxin 

 which was present in the milk. Between the fourth and 

 eighth day only -^ of the total antitoxin present was absorbed. 

 Using the milk from a normal woman, the observers added an 

 amount of antitoxin obtained from a horse which corresponded 

 to the amount present in the former experiment. In this case 

 they found that about -fa was absorbed within the first six days 

 after birth and about -j-^ was absorbed between the fourth and 

 the eighth days after birth. In this work experiments were carried 

 out to determine whether there was any evidence of horse protein 

 in the milk of the mother, that is to say, whether the antitoxin 

 passed out in the milk attached to the proteins of the horse serum, 

 or had been transferred to the proteins of the mother. No evidence 

 of the presence of horse serum in the milk could be obtained 

 either by the precipitin reaction or by the method of complement 

 deviation. 



These results were confirmed by further similar experiments 

 upon rabbits. 



Hamburger (i) did not, however, agree with the interpretation 

 of Much and his collaborators. He injected lactating rabbits with 

 tetanus antitoxin obtained from the horse, and stated that horse 

 antitoxin could be demonstrated in milk by the ordinary precipitin 

 test. Also he stated that evidence of the ' foreign ' protein which 

 must have been absorbed from the milk by suckling, could be ob- 

 tained in the blood of the young animal, by injecting the blood into 

 mice and ascertaining the presence of an antigen. The amount 

 of ' foreign ' protein present in the blood of the young was only 

 about -ffa of that found in the milk. 



Further experiments have been carried out by Romer (i) and 

 Romer and Sames (i) (1909) which confirmed the results previously 

 obtained by these investigators. It would not appear necessary 

 to consider these in any further detail, since the results were similar 

 to those previously considered. 



It seems evident that ' foreign ' protein can be absorbed by the 

 suckling animal in the early days of life, but that the absorption 

 proceeds on a very much smaller scale than in the case of a native 

 protein. Thus Ganghofner and Langer, using the precipitin method, 



