470 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



presumably in combination with a factor in the blood plasma, causing 

 coagulation of the fibrinogen more rapidly than that of another class. 



A similar type of specific adaptation between substances may influence 

 also the behavior of cells ; thus, according to Mudd, Lucke, McCutcheon and 

 Strumia, the macrophages and polymorphonuclear leucocytes of rabbits act as 

 phagocytes towards bacteria, and also towards erythrocytes and protein- 

 coated collodion particles, more efficiently if rabbits sera are used as the 

 carrier of bacteriotropin than when human sera are used. The same specific 

 relation is seen if immune serum is used instead of normal serum. The serum 

 with the tropin which it contains, or the globulin fraction of the immune 

 serum, is supposed to spread over and to attach itself to the surface of the 

 antigenic material. As a result of this effect the spreading-out and phagocytic 

 activity of the leucocytes are stimulated. Under these conditions the leucocytes 

 behave as if they were able to differentiate between the sensitizing substances 

 in the sera of two different mammalian species. 



Tillett and Garner, and subsequently Madison and Van Deventer, ob- 

 served that a filterable, heat-stable substance can be extracted from strepto- 

 coccus hemolyticus, which fibrinolyzes plasma. Substances from strepocccci 

 isolated from inner human organs dissolve human plasma and, slightly, 

 monkey plasma ; cultures of this kind are inactive towards the plasma clots of 

 other animal species, such as the rabbit. In streptococci isolated from horses 

 there is a fibrinolysin that is specific for horse plasma and the same applies 

 to swine streptococci and swine plasma. Addition of serum from the same 

 species, especially of anti-streptococci immune serum, inhibits the action of 

 the fibrinolysin in a specific way. By serial passage of a human streptococcus 

 through rabbits it is possible, according to Reich, to cause in the streptococcus 

 a loss of the human carbohydrate A and a loss of the fibrinolysin for human 

 plasma; instead, a carbohydrate characteristic of animals appears. By sub- 

 sequent serial cultures of the streptococcus on human blood agar plates, the 

 original characteristerics of this streptococcus are restored. 



In a somewhat related way, Duhey finds that the action of serum is 

 specifically adapted to red corpuscles of a certain kind.Thus the venom of 

 Synancya horrida is hemotoxic as well as neurotoxic. The hemotoxic action 

 against the red blood corpuscles of a given species of animals is much more 

 readily prevented through the addition of serum of the same species than by 

 that of the serum of a different species. Thus rabbit serum protects rabbit 

 corpuscles, while human serum protects human corpuscles; a species differ- 

 ential seems therefore to be attached to an inhibiting substance. 



A further analogous condition is noted in the interaction between blood 

 sera and the venom of heloderma; sera which do not activate the hemolytic 

 effect of this venom, inhibit it. Now in some cases hemolysis of the erythro- 

 cytes of a certain species seems to be especially inhibited by the blood serum 

 of the same species. Likewise, Besredka observed that sheep serum protects 

 sheep corpuscles, but not the corpuscles of another species, in a specific 

 manner against the hemolytic action of rabbit serum. 



In general, the blood serum of an individual is specifically adapted to its 



