KAKYOKINESIS. 201 



allowed to remain for twelve hours without harm. Generally an hour 

 will be sufficient. 



4. Wash in water. 



5. Dehydrate gradually, first placing in dilute alcohol, and after- 

 ward in stronger. The sections can now be kept in alcohol indefinitely* 

 If the tissue has been infiltrated with celloidin, the sections must 

 not be held in ninety-five per cent alcohol longer than five minutes, 

 as the infiltrating medium will be dissolved. 



6. Clarify with oil of cloves oil of bergamot for celloidin speci- 

 mens and mount in dammar. 



The method does not produce bright colors, but it gives a very 

 remarkable differentation of nerve tissue, by staining the medullary 

 substance violet, and the axis cylinders brown. It is particularly 

 valuable in pathological histology. 



BAYBERRY WAX INFILTRATING METHOD. 



In answer to many inquiries regarding the material used in this 

 process, I may say that Messrs. Eimer & Amend, chemists, of New 

 York, from whom my supply was originally obtained, state that the 

 article furnished me was the Japan wax. Dr. J. W. Blackburn, of 

 Washington, D. C., kindly informs me that this is the product of 

 Rhus succedanea. The material with which I have had the best re- 

 sults w<is of a very pale yellow or canary color. The darker speci- 

 mens are unsuitable. 



KARYOKINESIS. 



The phenomena attending cell-division are best shown in the thin 

 gill-plates or caudal fin of larvaB of the salamandra. Very fair 

 demonstrations may be made from rapidly growing tumors, as carcino- 

 matft, if after removal they are sliced thin and immediately fixed. 



Flemming's Fixing Fluid.* 



Chromic acid, 0.25 per cent \ 



Osmicacid, 0.1 " V in water. 



Glacial acetic acid, 0.1 " ) 



Half-an-hour's immersion will usually suffice, after which the tissue 

 is rinsed quickly in water and transferred to absolute alcohol, where it 

 may remain until ready to cut. The parts of larvae, above mentioned, 

 are of course sufficiently thin without sectioning. 



For staining, haema. or picro-carmine answer well, although saf- 

 * " Microtomist's Vade-mecum," Lee. London, 1885. 



