CONCERNING H.EMOLYSINS. 21 



A large part of these side-chains may, under suitable circumstances, 

 be thrust off and thus appear in the blood. 



Considering the large number of organs in the body and the mani- 

 fold chemistry of their protoplasm, it should not surprise us that 

 the blood, which represents all the tissues, can be filled with innumer- 

 able side-chains; and it is not at all astonishing, considering the 

 constantly changing chemistry of the organism (influenced by a large 

 number of factors such as race, sex, nutrition, labor, secretion, con- 

 ditions of the surrounding medium, etc.) that the serum should be 

 subject to constant qualitative fluctuations. Such variations are 

 seen in the examples already mentioned, showing the behavior of 

 sera of normal animals. Goat serum at one time possesses a slight 

 solvent action on sheep blood, at other times this is entirely absent. 

 Dog serum in one case dissolves the red cells of cats very strongly, 

 in another case it does not do so at all. The action of rabbit serum 

 on guinea-pig blood shows a special variability. 



A very interesting example is afforded by lamprey serum, which, 

 as is well known, possesses an extraordinarily toxic action for labora- 

 tory animals in general and also for red blood-cells in vitro. Dr. 

 Schonlein of Naples, whose recent death we lament, was kind enough 

 to experiment with this for us. His investigations showed that the 

 serum of a not inconsiderable number of lampreys possesses no 

 toxic action at all, so that it could be injected into rabbits intra- 

 venously in amounts of 2 cc. without any damage whatever. 



It is clear that this extensive variability enormously increases the 

 difficulties in investigating these sera. Thus on repeating the well- 

 known experiment of Buchner, whereby a mixture, in certain pro- 

 portions, of dog and rabbit sera loses its haemolytic property for 

 guinea-pigs in the course of twenty-four hours, we were able to com- 

 pletely confirm Buchner's results in three cases, while in five other 

 cases the haemolytic effect was only more or less lost. 



We believe that all these investigations support the view we have 

 already expressed regarding the nature of the complex poisons of the 

 blood-sera, v. Dungern (Muench. med. Wochenschr., 1899, No. 14), 

 basing his action on some new experiments of his, has accepted our 

 views. We can content ourselves, therefore, with merely mentioning 

 another view, recently expressed by Bordet l He has confirmed the 

 statements made by us regarding the fixation of the specific immune 

 body by means of the corresponding erythrocyte, and he has ad- 

 1 Annal. de 1'Instit. Pasteur, April 1899. 



