GENERAL PHYSICAL AND CHEMICAL PROPERTIES 29 



by itself. Rabbit's serum contains complement, but not the 

 specific amboceptor necessary for the laking of rabbit's corpuscles. 

 Accordingly, the addition of fresh rabbit's serum to heated dog's 

 serum restores complement to the latter, and thus it is again ren- 

 dered active for rabbit's corpuscles. The amboceptor is supposed 

 to unite on the one hand with certain groups in the corpuscle and 

 on the other with the complement, which is thus enabled to develop 

 its haemolytic action upon the envelope or the stroma. The com- 

 plement is incapable of acting, even in the presence of amboceptor, 

 if the temperature is reduced to o C. Nevertheless, the corpuscles 

 take up amboceptor at this temperature, and on this fact is based 

 a method of freeing serum from amboceptor. For example, if 

 dog's serum and excess of rabbit's washed corpuscles, both pre- 

 viously cooled to o C., be mixed and placed at o C. for some hours, 

 and the serum then removed, it will be found that it has lost the 

 power of laking rabbit's corpuscles, washed or unwashed, at air or 

 body temperature, although it will still do so on the addition of 

 dog's serum in which the complement has been destroyed by 

 heating it to 56 C. The real nature and mode of action of com- 

 plements and amboceptors are not yet satisfactorily determined. 

 The laws of chemical equivalents and definite proportions do not 

 seem to be observed in the reactions into which they enter. It has 

 therefore been suspected that the bodies in question belong to the 

 group of ferments, or are closely related thereto, and there is some 

 evidence that a fat-splitting enzyme, or lipase, is concerned in the 

 complement action (Jobling). 



As to the manner in which haemolytic agents cause the liberation of 

 the blood-pigment, the fact that in so many forms of laking the cor- 

 puscles swell up before the haemoglobin escapes indicates that the 

 entrance of water is an important step. The entrance of water is 

 favoured by changes produced in the chemical and physical condition 

 of certain constituents of the superficial layer (envelope) of the cor- 

 puscle, as well as by changes in its interior. Saponin and ether, for 

 example, are known to be solvents of cholesterin and lecithin, and 

 cholesterin and lecithin are important constituents of the stroma and 

 envelope of the erythrocyte. It is easy to understand that if a portion 

 of one or both of these substances is dissolved, or altered without being 

 actually dissolved, profound changes may be produced in the permea- 

 bility of the corpuscle to water and to the salts dissolved in the liquid 

 in which the erythrocytes are suspended. In addition to this change 

 of permeability, many laking agents, perhaps all, exert also a more direct 

 influence on the normal relations of the native blood-pigment to the 

 stroma. Ether and saponin, for instance, seem to act in two ways 

 by disorganizing the envelope through solution of its lipoids, and thus 

 increasing its permeability to water; and by helping to dissociate the 

 blood-pigment-stroma complex by exerting a pull on the lipoids of the 

 stroma, while the water simultaneously exerts a pull on the pigment. 



The conclusion follows from this view of haemolysis, that the erythro- 

 cytes, normally so perfectly adapted to the plasma in which they float, 

 may, when the conditions on which their equilibrium with it depends 



