THE ORGANIZATION OF THE PROTOZOA 41 



garded as a colony of bioblasts, imbedded in a fluid matrix, com- 

 parable in a general way to a zoogloea-colony of bacteria. 



A special and important class of metaplastic granules are the so-called 

 " deutoplasmic " bodies, consisting of reserve food- materials stored up in 

 the protoplasmic substance. Examples of such are the yolk-granules of ova, 

 the paraglycogen-grains of gregarines, the plastinoid bodies of coccidia, 

 starch-grains in holophytic forms, etc. 



Amongst the granulations of the protoplasm, special mention must be 

 made of the bodies known generally as chondriosomes and mitochondria, but also 

 by a variety of other names (cytomicrosomes, bioblasts, spherules or sphero- 

 plasts, and, collectively, ergastoplasm). The chondriosomes are not to be 

 classed with the temporary, metaplastic inclusions, but are permanent ele- 

 ments of the cell- protoplasm. The chondriosomes of Protozoa have recently 

 been the subject of detailed study by Faure-Fremiet (38'5). In the living 

 condition they are small transparent bodies, feebly refractile, and of a pale 

 grey tint. In shape they are generally spherical, and vary from 0*5 /i to 

 1'5 n in diameter. In some cases the chondriosome appears homogeneous in 

 structure ; in others it presents the appearance of a vacuole with fluid con- 

 tents and a denser peripheral layer. In contact with water or with weak 

 alkalis they swell up immediately. When the nucleus (in Infusoria the 

 micronucleus) divides, the chondriosomes also divide simultaneously, and the 

 daughter- chondriosomes are sorted out between the two daughter- cells ; 

 they have, however, no direct relation with the nuclear apparatus. In the 

 process of division each chondriosome becomes first rod-like, then dumb-bell- 

 shaped, and is finally constricted directly into two halves. 



A purely chemical definition of the chondriosomes, according to Faure- 

 Fremiet, cannot be given. They exhibit the reactions of a fatty acid, and 

 can be considered as combinations of fatty acids or of phosphates of albumin. 

 The physiological function of the chondriosomes is not clear, but Faure- 

 Fremiet considers that they " play an important part in the life and evolu- 

 tion of the sexual cell," in Protozoa or Metazoa, and are active in the elabora- 

 tion of deutoplasmic substances of fatty nature, into which they may be 

 transformed directly. 



It has been shown, however, that the minute granules of proto- 

 plasm do not lie isolated from one another, suspended freely in a 

 matrix, but are seen in the microscopic image to be connected with 

 one another by fine lines or darker streaks, the whole forming a 

 delicate network, at the nodes of which the granules are lodged. 

 In some cases the granule itself is perhaps only an optical effect 

 produced by a node of the network. On these appearances has 

 been founded the so-called reticular theory of protoplasm, connected 

 especially with the names of Heitzmann, Schafer, and others. On 

 this view protoplasm has been regarded as composed of an exceed- 

 ingly fine reticulum, a network or feltwork ramifying in all planes, 

 bearing the granulations at its nodal points, and bathed throughout by 

 a fluid, more or less watery sap, or enchylema. The fibrillar theory of 

 Flemming may be regarded as a modification of the reticular theory. 



Against the reticular theory of protoplasm, it may be urged that 

 it leads to physical difficulties, in view of the generally fluid nature 

 of protoplasm. For the reticulum must itself be either of a fluid 

 pr a o}jd nature ; if fluid, it presents the condition of one fluid 



