52 PEOTISTS AND DISEASE 



cryptomonads, found symbiotic with marine protozoa, &c. 

 In these cases the symbiosis is not so perfect as that of 

 lichens : the animal digests its companions when starvation 

 threatens. 



The green or yellow organisms have the structure of 

 algae : nucleus, chromatophore with pyrenoid, and cell- 

 wall of cellulose. Their occurrence is not constant in every 

 species of animal with which they associate. They have 

 been seen to divide inside their symbionts, and Famintzin 

 obtained divisions in a slide- and- cover culture. 



When infested animals are kept in the dark they eject 

 their zoochlorels. The latter have been isolated and culti- 

 vated, and identified with Chlorella vulgaris one of the 

 Protococcaceae. 



Caullery mentions that these organisms also were long 

 denied their real status in England. 



Mitochondria. In the higher animals and plants bodies 

 which stain like chromatin with iron-haematoxylin are 

 found in the cytoplasm. These bodies are called mito- 

 chondria or chondriosomes. They undergo changes in the 

 vital processes of the cells. Bayliss states that they are 

 composed of albumen and lecithin. Some of them resemble 

 bacteria very closely and one of the many theories of cancer, 

 that of Portier, is based on the assumption that they are 

 symbiotes, which cause cancer by assuming parasitic 

 characters. Facts that are recorded below render any 

 theory of cancer unnecessary. 



