PRECIPITINS. 115 



each species of animal differ from those of every other species, and 

 it certainly should convince us that it is impossible by any chemical 

 process to make cow's milk a perfect substitute for the mother's 

 milk in the feeding of infants. Fisch ^ found that rabbits treated 

 with an emulsion of the cells of the udders of animals furnish spe- 

 cific lactosera, and this demonstrates that milk is not a filtration 

 product, but that some of its important constituents result from the 

 transformation of the specific cells of the gland. Milk which has 

 been boiled for half an hour loses its power of forming a precipitum 

 on the addition of its specific lactoserum. 



Myers ^ prepared crystallized egg albumin from fresh eggs and by 

 repeated intraperitoneal injections of this substance into rabbits, he 

 obtained a serum that gives a dense precipitate when added to so- 

 lutions of crystallized egg albumin. This precipitate forms at or- 

 dinary temperature, but its formation is accelerated at 37°. It is 

 soluble in two per cent, sodium chlorid solution and such a solution 

 gives the ordinary proteid reactions. The serum of a rabbit treated 

 with egg albumin from the fowl forms a slight precipitate with the 

 albumin obtained from ducks' eggs. Ovasera have no precipitating 

 action on globulin obtained from sheep serum nor on that from bul- 

 lock serum, nor on serum albumin from the sheep or the bullock, nor 

 on pepton. Myers next prepared serum globulin from the blood of 

 the sheep and obtained from rabbits treated with this preparation a 

 serum which has no action on egg albumin or upon pepton, but does 

 give a slight precipitate with globulin obtained from buUock's serum. 

 The serum of a rabbit immunized against the globulin of the sheep's 

 blood also agglutinates the red corpuscle of the sheep. This un- 

 doubtedly is due to the presence in the red blood corpuscles of the 

 sheep of a substance allied to, if not identical with, the globulin ob- 

 tained from sheep's blood. It was also found that the globulin 

 serum agglutinates the washed red blood corpuscles of the fowl. 

 From these observations Myers draws the following conclusions : " It 

 follows from these facts that the product here called ' sheep's glob- 

 ulin ' is a mixture of substances. The main portion of the pre- 

 cipitum given by its precipitin is formed from a substance which is 

 not present in the ' serum globulin ' of the bullock. One substance, 

 present in small quantities in the sheep's globulin, is, however, also 

 present in buUock's globulin, since the precipitin of sheep's globulin 

 gives a small precipitum with bullock's globulin. This substance 

 common to the two globulins is not present in the red corpuscles of 

 the sheep or fowl, since the precipitin in bullock's globulin does not 

 agglutinate these corpuscles. Further, we must suppose that there 

 are two other substances in the serum globulin of the sheep, one 

 present in fowl's red corpuscles and the other present in those of the 



' St. Louis Gourier of Medicine, 1900. 

 2 The Lancet, Vol. U., 1900. 



