100 DR. ELIAS METSOHNTKOFF. 



operations, which they are also hardy enough to survive for 

 some time. 



If water holding carmine or indigo in suspension be injected 

 beneath the epidermis of the animal under observation, the 

 particles of colouring matter are after a very short time taken 

 up by the amoeboid cells. In Phyllirhoe, there are two kinds 

 of amoeboid cells, of which only the smaller ingest colouring 

 matters in this way. The larger cells which often assume very 

 curious forms, are distinguishable by their vacuolated proto- 

 plasm, and by containing no foreign bodies ; in a Phyllirhoe 

 which had been injected with powdered carmine, these large 

 cells contained rosy patches, caused by dissolved carmine. In 

 spite of repeated trials, I could not ascertain the way in which 

 the carmine entered them. The smaller granules of solid 

 carmine were all eaten by the small cells, in a manner pre- 

 cisely similar to that already described ; the larger masses were, 

 on the other hand, surrounded by a sort of plasmodium of 

 small cells, which came one by one to each lump, and flattened 

 themselves upon it, fusing with neighbouring cells as these 

 arrived. In this way arose plasmodia of very different sizes, some 

 even visible to the naked eye, which may be compared to the 

 giant cells so often described in Vertebrates. This observation, 

 which I have often repeated, confirms the opinion of Weiss,^ 

 Koch,^ and others, that giant cells are often found in the 

 neighbourhood of foreign bodies. In all cases in which I have 

 found giant cells in Invertebrates, they have arisen round 

 foreign bodies, and always by the fusion of separate cells. My 

 results are therefore opposed to the view, held by some patho- 

 logists, that giant cells are formed by absorption of pus cells, or 

 by a process of incomplete fission, arrested after division of the 

 nucleus. Other observers, who have studied Invertebrate blood- 

 corpuscles outside the body, have described their great tendency 

 to form Plasmodia, without the presence of foreign particles. 



' " Ueber die Bildung und die Bedeutung der Riesenzellen, &c.," ' Virchow's 

 Archiv,' Bd. Iviii, p. 13. 

 2 ' Berliner klinische Wochenschrift,' 1882, No. ] 5. 



