90 PROTOPLASM 



isolated they appear moderately refractile, with a rather 

 broad dark border and somewhat clear interior. It would 

 be difficult to say whether this border is a structural reality, 

 or only an optical phenomenon such as is shown by every 

 small globule. The bodies are remarkable for the intense 

 readiness with which they are coloured by eosin or gen- 

 tian violet, and with Delafield's hsematoxylin also they 

 can be tinged a light reddish colour. The protoplasmic 

 framework is tinged very little by any of the staining fluids 

 mentioned, most, however, by gentian violet dissolved in 

 aniline water. 



It appears that the bodies described are of widespread 

 occurrence in the protoplasm of the Ciliata. Whether they 

 are in part identical with the singly refracting corpuscles 

 mentioned by Maupas appears to me doubtful. On the 

 other hand, they can certainly be ranked with the cell 

 granules described by Altmann. 



In the above-mentioned Zoothamnium I devoted some 

 attention to the strongly developed stalk muscle, since, as 

 is well known, a fibrillar structure has often been ascribed 

 to the muscle thread of this genus. In the living condition 

 I could only observe a quite feeble longitudinal striation in 

 the thread. After death, however, the fibrillar nature shows 

 up very beautifully, and at the same time it is seen that 

 the fibrillse are connected in the transverse direction by 

 numerous delicate lines, so that the structure is one com- 

 posed of elongated meshes (Plate XII. Fig. 4). 



I have already pointed out several times that the macro- 

 nuclei of Ciliata possess a very finely meshed structure. 

 On the occasion of the investigations on Paramcecium cau- 

 datum just described I was able to convince myself again 

 of the fact. If Paramcecia be killed with iodine- alcohol 

 (alcohol of 45 per cent tinged light yellowish brown with 

 iodine), and then stained as intensely as possible witli 

 Delafield's haematoxylin, and broken up into little frag- 

 ments in oil of cloves, particles of the protoplasm (Plate 

 IV. Fig. 8, a) are found intermingled with particles of the 

 macro-nucleus (Plate IV. Fig. 8, 6). The latter can easily be 

 recognised from the fact that their framework, very similar in 



