112 HUNTER. [Vol. II. 



on the centrosome in the tendon of Achilles of the frog. Meves 

 thinks the centrosome a permanent cell organ which in old cells 

 may not be functionally active. Von Lenhosseck points out that 

 Meves's observations were made on winter frogs, and thinks that 

 perhaps with the renewal of life activities the cell might divide 

 again. The author has not yet concluded any experiments in 

 this direction, as his material was limited to a killing period of 

 three months, June to September. Such experiments in CyntJiia 

 would be difficult, because probably no actual hibernation period 

 takes place, although the life activities may be reduced in 

 winter. One interesting fact might be noted, however ; if the 

 central ganglia of several specimens, killed in the same fixing 

 fluids and exposed to same conditions of technique, are sectioned, 

 stained in iron-haematoxylin, and examined, it is found that 

 some specimens show nearly all the cells of the ganglia to con- 

 tain centrosomes and spheres, with accompanying indentation 

 of the nuclei, while other specimens show few if any cells in 

 this condition, and the centrosome, if present, not surrounded 

 with a sphere or radiations. In other words, at a given time of 

 the year (summer), certain ganglion cells in some animals are 

 observed to contain centrosomes, while corresponding cells in 

 other animals seem to lack this structure. It is important to 

 note that the age of the specimens cannot be taken into 

 consideration, and this may be an important factor. 



It seems to the writer that the centrosome in the ganglion 

 cells must have a meaning other than cell division. Might it 

 not serve the same function as it appears to have served in 

 certain cells possessed of protoplasmic movement, such as leu- 

 cocytes, giant cells of bone marrow, embryonic blood corpuscles, 

 pigment cells, etc. } In leucocytes it has been shown by Flem- 

 ming ('91) and Von Rath ('95) that the centrosome is apparently 

 not engaged in mitotic division, as a sphere and central body 

 are found existing in cells in which the nuclei are divided, seem- 

 ingly by amtosis. In the liver cells of an isopod i^Porcellid) the 

 attractive sphere is not concerned in the division of the cell. 

 Other like cases have been observed. In such cells as the pig- 

 ment cell the centrosome appears to be a dynamic center, caus- 

 ing contraction or expansion (chromatophore of cephalopods). 



