KLECTRICALLY STIMUI.ATKI) OANOLKIN CKLI.S. 9 



(U'vico has given me, incidentally, a permutation of 

 iiardeningand stainingcombinations which might well 

 form the basis of a separate study. 



In this way not only may a dozen specimens be 

 manipulated as easily as one, but they are held in the 

 desired positions relative to each other and, of special 

 importance, they are cut together. However perfect 

 the microtome, sections do not come from it of abso- 

 lutely uniform thickness ; and where minute, or even 

 gross, differences of staining are to be studied, this is 

 of prime importance. 



Apropos of Korybutt-Daszkiewicz's work, I have 

 sections, no thicker than his and obtained by essen- 

 tially the same method, which show a most striking 

 differentiation into red and blue nuclei. It requires but 

 little focusing, however, to demonstrate that the red 

 nuclei occupy the superficial, and the blue the deeper, 

 layers of the section. A slight difference in the thick- 

 ness of the section might thus change the proportions 

 of the two quite materially. The thinner the section, 

 according to the above, the larger would be the pro- 

 portion of red nuclei. That this may be an explana- 

 tion for Korybutt-Daszkiewicz's result is indicated by 

 the fact that in equal areas of section he finds nearly 

 400 (4127 to 3759) nuclei less in the stimulated than in 

 the control cords. This would suggest that the sections 

 of the stimulated cords are thinner than those of the 

 control ; and from these he gets his preponderance 

 of red nuclei. 



The essential feature, then, of my method is that it 

 compares corresponding ganglia of the same animal 

 which have been subjected to identical treatment in 

 passing from the animal to the slide ; the onhj point 

 of difference (jeiiig that the one has had its nerve stim- 



