Antibodies in General 9 



immunity to cholera, led to results of great importance. It is however 

 especially the studies upon the specific haemolysins which have helped 

 to further our knowledge concerning immunity. The results with the 

 haemolysins show that these and the bacteriolysins are both strictly 

 comparable in their mode of production and constitution. In both the 

 injection of cellular elements is followed by the appearance of specific 

 lysins in the serum of the treated animal. The cytolytic serum is 

 rendered inactive by heat (56 C.) and can be reactivated by fresh serum 

 which of itself is without effect. The action between cytolysin and cell 

 has been compared by Ehrlich to that which takes place between toxin 

 and antitoxin. In the case of the cytolysins we have to deal with a 

 stable immune-body and a labile complement, which cannot act of itself 

 but requires the intermediation of the immune or intermediary body. 

 When this is secured, the complement produces changes of a digestive 

 character in the cells subject to its action, and for this reason it may be 

 safely considered to possess the character of a digestive ferment. The 

 similarities observed in these antibodies led to the extension of the 

 theory of Ehrlich to other antibodies such as the agglutinins and 

 precipitins. 



It appears therefore that all antibodies are formed on the same 

 general principles, although they may possess different properties. 

 Wherever they are formed the substance must be assimilable which 

 gives rise to their formation. Toxins are relatively simple bodies, they 

 are highly soluble and readily enter into combination with the proto- 

 plasmic molecule through the intermediation of the haptophorous group. 

 Food-stuffs on the other hand are more complicated, they require to be 

 simplified for assimilation, and in consequence the antibodies to which 

 they give rise must necessarily be more complicated. In the latter 

 case the albuminous molecule anchors the food-stuff by means of 

 receptors, which act as intermediaries, permitting a digestive, ferment- 

 like group (complement or the like) to attack the complicated food 

 molecule. 



Before proceeding to consider antibodies in general I will add a few 

 facts regarding the antitoxins in particular. When an animal is being 

 immunified against a toxin, say tetanus or diphtheria toxin, the antitoxin 

 content of its serum and milk gradually rises, as periodic injections of 

 increasing doses of toxin are being practised. Brieger and Ehrlich 

 (1893, p. 341) noted however that the curve of antitoxin content 

 pursued a wavy course (wellenfdrmiger Verlauf) in animals treated 

 with tetanus toxin, the milk containing antitoxin in lesser quantity 



