520 C. CLIFFORD DOBELL. 



chambers are often indistinctly seen, or absent. Vacuoles are 

 not infrequently present. Red "chromatin" structures of 

 varying form are seen in different individuals and at different 

 points in the same individual. Fig. 10 shows some of the 

 " unclear " structures observable in dried organisms. It is 

 drawn from a part of a Cristispira which was dried before 

 fixation, fixed in absolute alcohol^ and stained by Gienlsa^s 

 method. It will be seen that the " chromatin" is in the form 

 of spiral or zig-zag filaments, rods, granules, "tetrads," etc. 

 These arrangements of the "chromatin" are found, side by 

 side in the same organism at the same time. 



The appearances which are observable in organisms which 

 have undergone plasmoptysis are instructive. Such an indi- 

 vidual is shown in fig. 3. The whole organism is filled with 

 red granules, of variable size and irregular distribution. At 

 the points where the cell membrane has burst, the protoplasm 

 has flowed out, and it can be seen that it consists of two 

 different substances — a bluish or lilac coloured substance and 

 a denser dark-red substance. 



How are all these different appearances to be interpreted ? 

 I believe the correct interpretation is as follows : The 

 structui-e of Cristispira may be compared with that of a 

 bamboo stem. The whole body is in the form of a liolloAV 

 cylinder, divided into a single series of chambers by means of 

 a series of transverse disc-like partitions like the nodes of a 

 bamboo rod. The cytoplasm forming the walls of the cylinder 

 and the disc-like partitions is dense and deeply stainable ; the 

 cytoplasm which fills the chambers is less dense and less 

 deeply stainable. Text-fig. 1 illustrates diagrammatically the 

 structure of a portion of a Cristispira which is supposed to 

 have been split longitudinally, so as to divide the body into 

 two equal parts. When viewed from inside, an appearance 

 such as is shown u\ Text-fig. 1 Avould be seen. 



The tube forming the body is divided into cylindrical 

 chambers by transverse disc-like partitions — only half of each 

 disc and chamber being seen, of course, when the other half 

 is split off. In a Cristispira all the solid structures dia- 



