CYTOPLASMIC INCLUSIONS OP THE GERM-CELLS. 597 
i'Hozomatic material was taken up in the formation of the 
spindle, I think rather vitiates the evidence for the view that 
it is necessarily the Nebenkern part of the idiozome (archo- 
plasm) which goes to form the middle spindle. Term's 
material seemed to admit of clearer study of the Nebenkern 
than mine, because in the snail the mitochondria do not 
appear to become localised to one side of the cell as often 
happens in Geotriton, according to Terni. This localisation 
often clears the area around the Nebenkern, and assists 
observation. (For further evidence against the “ ISTebenkern 
spindle” view see Faure-Fremiet, page 580 and fig. 33). 
To return to the Nebenkern of Helix aspersa, it may be 
worth while to attempt to analyse some of the variations so 
strikingly evident. 
The Nebenkern rods differ in number without a doubt; 
they likewise differ in size, and their shape is seldom the 
same. Neither the number nor the great difference in size 
can be the result of varying conditions of fixation. For the 
shape I cannot speak with such confidence. It is quite 
possible that some small variation either in the fixative or the 
•condition of the cell might produce distortion of the rods. 
To test this I examined a great deal of material by the intra- 
vitam methods. Janus green of the strength of 1 in 30,000 
and neutral red about the same strength were used. These 
did not give very good results. After many experiments I 
found that infra- vitam methods would not properly settle the 
question, because the rods of the Nebenkern never seemed to 
take the stain heavily enough. 
I devised the following “ fresh method” : A small part of 
the ovotestis was smeared on a slide, and a little 1 per cent, 
permanganate of potash was added. A coverslip was then 
placed over this, and the preparation, after about sixty 
seconds, showed the cell inclusions a brown colour, and they 
were very easily studied. The mitochondria were remarkably 
•clear, and were of the spherical type, not stick or rod-like. 
The Nebenkern was found to vary as in my drawings — rod- 
shaped or curved. In this permanganate method the cells are 
