CONTRIBUTIONS TO THE THEORY OF LYSIN ACTION. 



action over to these cells. From this we see also why the digestive 

 action becomes manifest only on the addition of immune body. 

 This brings the ferment, present in the serum fluid in such small 

 quantity, to the blood-cells in comparatively large amounts, thur:- 

 concentrating and increasing its action. It is possible and even 

 probable that only a few substances with digestive properties exist 

 in the blood, perhaps only one; but that a countless variety of specific 

 immune bodies can exist there, as Gruber, among others, assumes. 

 In that case we must assume that in these immune bodies there is 

 always one group which fits only to the cells or substances used to 

 excite its production, but that all these immune bodies possess an 

 atomic group in common which effects the combination with the 

 digestive substance. On this assumption it is very easy to explain 

 by means of the side-chain theory the otherwise difficult problem 

 of the mode of origin of the lysins. According to Ehrlich's definition, 

 the side-chains possess definite atomic groups which are able to com- 

 bine with certain other atomic groups and so increase the proto- 

 plasmic molecule. As far back as 1885 (Sauerstoff Bediirfniss des 

 Organismus) Ehrlich had pointed out that the atomic groups thus 

 anchored to the living substance were much more readily oxidized 

 and that they therefore represent the nourishment (KCXT egoxrfv} of 

 the cell. The study of immunity has considerably extended this view 

 and taught us that the antibody represents such thrust-off side- 

 chains; further, that the immunizing process consists in forcing the 

 particular organism to produce these side-chains in surplus amount 

 in conformity with Weigert's theory of cell injury. It is of course 

 very probable that these side-chains, according to their special func- 

 tion, will be differently constituted. If a side-chain is designed 

 to assimilate relatively simple substances, we may believe that the 

 possession of a single combining group will suffice. Very likely the 

 side-chains which anchor toxins are of this simple type. Eut it is 

 entirely different w r hen a giant molecule (albumin molecule) is to be 

 assimilated. In this case the anchoring of the molecule is only a pre- 

 liminary requisite. Such a giant molecule is useless to the cell and 

 can only then be utilized when it is broken up by fermentative pro- 

 cesses into smaller parts. It will be particularly advantageous to 

 the cell if its "grasping arm" is at the same time a carrier of a fer- 

 mentative group which can at once be brought to bear on the anchored 

 molecule. We see such well-adapted contrivances (in widen the 

 grasping apparatus also possesses digesting properties) in a whole 



