THEORIES OF IMMUNITY. 



especially that of the emigration of the leuco- 

 cytes, but the theory made to fit the facts did 

 not appeal to him, and he saw at once that study 

 of inflammation among lower animals of the 

 simplest type and organization would certainly 

 throw light on this process in the vertebrates, 

 as well as in the frog — the animal upon which 

 Cohnheim's experiments had been made. 



Since, in the atrophy of the larval organs of 

 the synaptera, the essential part is played by 

 the ameboid cells of the mesoderm which col- 

 lects in masses there, possiblj the inflammatory 

 exudates manifest some especially important 

 function by their richness in white corpuscles. 

 So that it suggested itself to him to introduce 

 splinters through wounds under the skin of 

 transparent marine animals; if the supposition 

 was correct there should appear a collection of 

 ameboid cells at the point of irritation. Choos- 

 ing " bipinnaires," — the large embryonic forms 

 of star-fish, — he stuck rose thorns in them, and 

 these were seen to be at once surrounded by 

 masses of ameboid cells, exactly as in man after 

 the introduction of a splinter or other irritant 

 substance. In other words, the first point was 



14 



