132 



MICROBES AND TOXINS 



to the injury by movements of attraction or repulsion 

 (varying according to circumstances) of its protoplasm. A 

 foreign body introduced into it is engulfed and then rejected. 



FIG. 44. Plant filament surrounded by the phagocytes of Spongilla. 

 (Metchnikoff.) 



If into the body of a sponge a little glass tube or an asbestos 

 fibre or any sharp foreign substance is introduced, motile 

 amoeboid cells from the mesoderm soon come and surround it, 

 the same cells which are capable of surrounding and digesting 

 both inert granules and living prey. This engulfing power of 



phagocytes 



FIG. 45. Mass of phagocytes 

 round a spike in Bipinnaria 

 asterigeria. (Metchnikoff.) 



FlG. 46. Phagocytes of the 

 worm collected round 

 a foreign body. (Metch- 

 nikoff.) 



the mesodermic cells (and of certain endodermic cells also) is 

 aided by the sensitive contractile ectodermic elements. 



The larvae of a certain sea-anemone (Astroptcttn ptntacanthus\ 



