Jelliffe, Cytology bf the Brains of Some Amphibians. 149 



minutes, decolorizing by Nissl's decolorizer or by 95 % and 

 absolute alcohol which gave precisely the same pictures, 



Thionine blue as recommended by Lenhossek was tried 

 and, while it stains very intensely, the writer found it difficult 

 to deal with. 



These experiments seem to show the following : 



1. With reference to gross changes due to fixing agents : 

 In the illustrations, six cross sections are figured, which show 

 for themselves. As far as could be made out, absolute alcohol, 

 95 c/(j alcohol and alcohol sublimate acted in almost exactly the 

 same manner ; distortion and contraction were great and seem- 

 ingly evenly distributed in the grey and the white matter. With 

 equal volumes of 205^ formalin and 95^ alcohol, the distor- 

 tion and contraction was much lessened, while formalin 20^ 

 was almost like the normal cord. With Hermann's and 

 Flemming's solutions, the contraction was extreme, the gray 

 matter seemingly more strongly acted upon. Thus if external 

 form, alone would be the guide, formalin 20% gives the best 

 preservation. 



2. In looking upon the effect upon the ganglion cells and 

 their minute structure, a different state of things is shown, the 

 correct interpretation of which would seem to be an extremely 

 difficult matter. In the first place, one can not get the body 

 of the same ganglion cell under these various conditions, which, 

 perhaps in a hypercritical sense, vitiates the results ; then the 

 various angles at which a cell may be cut should be taken into 

 account ; but taking the ganglion cells as they run and choos- 

 ing those of the larger so-called motor type of the ventral horns, 

 the following conclusions seem warranted by the experiments 

 made. 



Between alcohol 95^, and sat. alcoholic sol. of corros. sub. 

 I could detect no essential points of difference. With absol. al- 

 cohol, the differences made out were very slight, the pictures 

 being of greater definiteness and sharpness than with the former 

 two reagents. In all three there is contraction of the body 

 of the ganglion cells but as the rest of the cord contracts about 



