72 PROTOZOOLOGY 



In certain Protozoa, the chondriosomes are not always demon- 

 strable. For example, Horning states in Monocystis the chondrio- 

 somes present throughout the asexual life-cycle as rod-shaped bodies, 

 but at the beginning of the spore formation they decrease in size and 

 number, and in the spore none exists. The chondriosomes appear as 

 soon as the sporozoites are set free. Thus it would appear that the 

 chondriosomes are reformed de novo. On the other hand, Faure- 

 Fremiet, the first student of the chondriosomes in Protozoa, main- 

 tained that they reproduce by division, which has since been con- 

 firmed by many observers. As a matter of fact. Horning found in 

 Opalina, the chondriosomes are twisted filamentous structures and 

 undergo multiple longitudinal fission in asexual division phase. Be- 

 fore encystment, the chondriosomes divide repeatedly transversely 

 and become spherical bodies which persist during encystment and 

 in the gametes. In zygotes, these spherical bodies fuse to produce 

 longer forms which break up into elongate filamentous structures. 

 Richardson and Horning further succeeded in bringing about divi- 

 sion of the chondriosomes in Opalina by changing pH of the medium. 



As to the function of chondriosomes, opinions vary. A number of 

 observers hold that they are concerned with the digestive process. 

 After studying the relationship between the chondriosomes and 

 food vacuoles of Amoeba and Paramecium, Horning suggested that 

 the chondriosomes are the seat of enzyme activity and it is even 

 probable that they actually give up their own substance for this 

 purpose. Mast and Doyle hold that the "excretory granules" (chon- 

 driosomes) in Amoeba proteus contribute to the formation of the 

 contractile vacuole. The view that the chondriosomes may have 

 something to do with the cell-respiration expressed by Kingsbury 

 was further elaborated by Joyet-Lavergne through his studies on 

 certain Sporozoa. That the chondriosomes are actively concerned 

 with the development of the gametes of the Metazoa is well known. 

 Zweibaum's observation, showing an increase in the amount of fatty 

 acid in Paramecium just prior to conjugation, appears to suggest 

 this function. On the othr hand. Calkins found that in Uroleptus, 

 the chondriosomes became abundant in exconjugants, due to trans- 

 formation of the macronuclear material into the chondriosomes. It 

 may be stated that the chondriosomes appear to be associated with 

 the formation of enzymes which participate actively in the processes 

 of catalysis or synthesis in the protozoan body. The author agrees 

 with McBride and Hewer who wrote: "it is a remarkable thing that 

 so little is known positively about one of the 'best known' proto- 

 plasmic inclusions." 



