572 BACTERIOLOGY. 



corpuscles (haemolysis) in a test-tube. In an analogous 

 way, if such tissue-cells as epithelium or spermatozoa 

 be injected repeatedly into the tissues of animals, the 

 serum of the blood of those animals acquires the power 

 of dissolving (digesting) such cells outside the body ; 

 and if so inert a secretion as milk be injected into the 

 tissues, the blood-serum of the animal receiving the 

 injections after a time reacts specifically with that milk 

 in a test-tube i. e., precipitates it. From the foregoing 

 we see that in the numerous phases and expressions of 

 this physiological possibility there are produced anti- 

 bodies having functions totally different from those 

 attributed by Ehrlich to antitoxins i. e., we have 

 "lysins," "agglutinins," "precipitins," "aggressins," "op- 

 sonins," etc., that in their mode of action suggest ferments 

 with specific affinities. It is evident that when broadly 

 conceived the mechanism of immunity comprehends very 

 much more than the neutralization of a bacterial toxin 

 by an antitoxin ; and, what is more to the point, in 

 many of these conditions of immunity or tolerance above 

 noted antitoxins as we know them, are not present at all. 

 In an important series of papers on the hsemolysins 

 published by Ehrlich and Morgenroth 1 an effort is 

 made to elucidate further the finer mechanism of im- 

 munity in its broad sense and various expressions, 

 and to adapt the side-chain doctrine to those more 

 complicated phenomena in which immunity depends not 



i Ehrlich und Morgenroth: Berliner klinische Wochenschrift, 1899. 

 Bd. xxxvi. S. 6 and 481; 1900, Bd. xxxvii. S. 453 and 681; 1901, Bd. 

 xxxviii. S. 251, 569, 598. See also Schlussbetrachtung: Ehrlich, in 

 Nothnagel's Speciellen Pathologic und Therapic, Bd. viii. Theil i. 

 HeftS, S. 161. 



