1889-90.] MORPHOLOGY AND PHYSIOLOGY OF THE CELL. 251 



tail may fuse with the head ; in the latter case the crescentic cavity 

 persists ( /). The safranophilous substance gradually disappears from the 

 thin band representing the remains of the tail, till finally its staining capa- 

 city is scarcely marked in some of the forms, although its density is notice- 

 able. This sketch of the organism developed out of the comma-shaped 

 body explains thus the occurrence of a denser, frequently more deeply 

 staining zone at one side, the presence of a crescentic cavity, or of a cavity 

 next the zone, and the frequently excentric position of the nucleus in the 

 adult organism (Figs. 3 and 4). In individual cases, in which these pecu- 

 liarities are apparently wanting, it may be that they cannot be observed, 

 because the organisms are not favorably placed in the microscopic field. 



We can, I think, now account for many of the forms shown in Fig. 9, 

 especially those in which a deeply .stained crescent occurs with a sphere 

 in its cavity — they are merely comma-shaped parasites in the process of 

 transformation into that stage in which sporulation takes place. In the 

 same way we may explain some of the forms illustrated by Luk- 

 janow,* especially his Figs. 14, 15, 16, 6ia and d, 66, 72, 74 and 75, and 

 probably also Figs. 7, 1 1, 13, 68, 69, yy and 94. His Fig. 48 would seem 

 to indicate that he saw the sporulating phase of the same organism. 

 All his studies were made on the gastric mucosa of the salamander. I 

 have found in the gastric mucosa of Diemyct^ihis very few abnormal 

 structures of this character. If they are parasitic, their comparative 

 absence from the stomach may be attributed to the digestive and 

 resistent action of the gastric mucosa, and it is probable that the irregu- 

 larity and atypical character of many of the structures drawn by Lukja- 

 now may be due to the physiological action, during life, of the glandular 

 elements in which they occurred. 



It is interesting to note the structure of the cytoplasm around the 

 full-sized organisms (Figs. 3-7). It is constituted of very fine rodlets, 

 each with a thick end directed towards the organism and passing in a 

 radiating manner peripherally into a zone of what appears to be finely 

 granular protoplasm, but which is, probably, a portion of the cytoplasmic 

 reticulum condensed. The border of thickened points in many cases 

 closely resembles a membrane. It depends, apparently, on the vitality of 

 the cell whether the radiating arrangement of the cytoplasm occurs or 

 not. It may be absent, as in Fig. 2, when the cell shows signs of 

 degeneration. It is difficult to understand the function of this mechanism, 

 but we may suppose it to act as a filtering apparatus. 



'Op. cit. 



