PHAGOCYTES AND RESORPTION. 309 



those which are grouped among the senile atro- 

 phies, is of interest to pathologists. In sclerotic 

 atrophy of the ovaries the large lymphocytes in- 

 vade the tissue, surround and destroy the ova and 

 follicular epithelium and eventually, as fibroblasts, 

 participate in the formation of fibrous tissue which 

 to a degree is substituted for the original struc- 

 ture. In old individuals or in those of failing 

 mentality it is said that ganglionic cells are found 

 in a greater or less degree of atrophy because of 

 the action of certain mononuclear phagocytes 

 (neuronophages) which are contiguous to or form 

 a zone around the cell. The neuronophages may 

 represent mononuclear cells from the blood or 

 those of proliferated neurogliar tissue. The best The 

 examples of this condition were found in very old ins 

 clogs. The chromophores of the skin, according to 

 Metchnikoff, may be considered as chromophages. 

 Whether or not they are of epithelial origin, as he 

 claims, they are said to exist normally in the hairs 

 in a latent or inactive condition. As old age comes 

 on, or as a result of other obscure causes, their 

 attitude becomes an active one, and they proceed 

 to take up and digest the normal pigments of the 

 hairs. Hence, white hairs are the result of an 

 autoparasitism by certain mononuclear phago- 

 cytes. In muscular atrophy it is held that the 

 sarcoplasm takes up the striated tissue after the 

 manner of phagocytes. 



We come into closer touch with our general sub- Reaorption 

 ject of immunity when we consider the resorptive cln^. rei8rn 

 function of the phagocytes for cells which are for- 

 eign to the host, for example, toward erythrocytes 

 which are injected for the purpose of producing a 



