56 LIFE: ITS NATURE AND ORIGIN 



first defeat for the Government under this Act. In this case I 

 had volunteered my services as expert because I was then inter- 

 ested in gelatin and its uses, and furthermore because my investiga- 

 tions had shown me not only the justice of the manufacturers' 

 position, but also certain scientific data which had an important 

 bearing on the matter. 30 



At that time I had begun to make experiments with protective 

 colloids, and soon noticed the powerful effect of gelatin on crystal- 

 lization, e.g., on plaster of Paris. 31 Experiments with cow's milk 

 showed that gelatin and gum arabic stabilize it against coagulation 

 by acid and rennin, and ultramicroscopic examination checked 

 the results. On comparing the composition of cow's milk with 

 that of human milk, and separating the "total protein" figure, 

 commonly used, into casein and lactalbumin, the superiority of 

 human milk in the protective colloid lactalbumin became mani- 

 fest. The fact that cow's milk can be stabilized by protectors is of 

 importance, because large curds, though suitable for a calf, are 

 not readily handled by an infant; and furthermore, casein entraps 

 the fat globules when coagulating, giving greasy curds which are 

 very hard for an infant to digest. 32 



The literature showed that many types of protective colloids 

 have been used for years in many countries in adapting cow's milk 

 to infant feeding. Professor Abraham Jacobi, later President of 

 the American Medical Association, had long advocated 33 the use of 

 gelatin and gum arabic, and stated that asses' milk is "a refuge 

 to which mothers fly when other milk or mixtures are not toler- 

 ated." Cereal gruels, dextrinized starch, seaweed (Irish moss), 

 lichens (Iceland moss), and beer (the dark dextrinous beer of 

 Bavaria) are among the many protectors used, and at present, com- 

 mercial dextrose, and maltose quite high in dextrin content are 

 popular. With milk mixtures high in fat, like ice cream, colloidal 

 protectors are desirable from the digestive standpoint; and many 

 can tolerate an eggnog better than raw milk, with or without the 

 alcoholic noggin. 



In the course of these experiments, an attempt was made to simulate 

 milk by forming a precipitate of calcium phosphate in the presence of 

 colloidal protectors. Protected sodium phosphate was mixed with 

 calcium chloride, and vice versa, but a stable sol did not result. In 

 following mentally what must take place in the mammary gland, it was 

 realized that as all body fluids contain protectors, both of the reacting 

 solutions should contain protectors. Thus was born the concept of 



