134 



MICROBES AND TOXINS 



attempt to destroy them by digestion : a struggle takes place, 

 sometimes the Daphnia is victorious, sometimes it succumbs. 



In tlie young of a vertebrate, the axolotl, if the non-vascular 

 rudiment of the fin is pricked with a needle charged with a 

 little carmine or indigo powder, the migratory cells can be seen 



"^^^ 



Fig. 50. — Two leucocytes of Daphnia sur- 

 rounding a conidium of Monospora. 

 (Melchnikofif.) 



Fig. 49. — Spores of Mono- 

 spora, surrounded by 

 leucocytes of Daphnia. 

 (Metchnikoff.) The spore 

 is transformed into 

 granules. 



Fig. 51. -An amoeba {Amoeba verrucosa) 

 incorporating a filament of Oscillaria. 

 (After Rhumbler.) 



hastening to the injured point and engulfing the particles. In 

 the older stages of the axolotl and in the tail of tadpoles, where 

 a well-developed vascular system exists, inflammation is accom 

 panied by a dilatation of the vessels and by diapedesis : the 

 reaction is more violent, but the essential process is the same 

 as in the non- vascular invertebrates. 



" It is quite evident that inflammation in the vertebrate, in 

 which the protective phagocytes emerge from the vascular 

 system to attack the aggressor, differs from the analogous 

 phenomena in the invertebrate only from the purely quantitative 

 standpoint. . . . The morbid phenomena, properly speaking, such 

 as the lesion or the primary necrosis, equally with the processes 

 of repair which succeed the inflammation, do not belong to it 

 and must not be confused with it " (Metchnikoff). 



The phenomena of vascular dilatation and hypersemia are no 



