224 MICROSCOPICAL RESEARCH IN THE 



recently published by Flemming. The following is a summary of 

 the more important conclusions reached by Flemming * : — 



A. For Nuclei in general.— i. Objects hardened in chromic 

 acid (i-io per cent, to \ per cent). 



The time will vary according to the nature of the object. 



2. Carefully washed in distilled water. 



3. Stained directly, or further hardened in weak, and then in 

 strong alcohol. 



Safra?iin, Magdala red (rose de napthaline) and dahlia (mono- 

 phenylrosanilin) give the best staining. Safranin prepared as given 

 above ; magdala in the same way ] dahlia is best dissolved in 

 water, or acetic acid. 



Only very small objects, or thin sections, can be successfully 

 stained, and these should be left in the fluid 12-24 hours. 



4. Objects transferred to weak alcohol (70 per cent.) and 

 shaken for a few moments ; then placed in absolute alcohol for 

 half a minute or longer, till no visible clouds of colour appear. 

 The process of decolouring is now completed, and the objects 

 must be at once removed from the alcohol, otherwise the colour 

 will be too much weakened. If it be required to examine the 

 objects before mounting, they may be removed to distilled water, 

 in which the colour of the nuclei will remain unchanged for a con- 

 siderable time. They must then pass through alcohol again before 

 mounting. 



5. Clarified in clove-oil and mounted in dammar-lac.\ 

 Clove-oil withdraws the colour a little, and hence it must not 



be allowed to work too long. Creosote extracts the colour still 

 more rapidly than clove-oil. 



B. Eggs of Echinoderms.J — In his recent researches on kary- 

 okinesis, Flemming states (p. 5) that he obtained serviceable 

 staining of nuclei in the following ways : — 



I. — Living eggs coloured on the slide^ either with safranin or 

 a?iiline dyes, followed by acetic acid (i per cent.), which is allowed 



* Flemming. Archiv. f. Mik. Anat., Vol. XIX., p. 321. 



\ Probably balsam dissolved in chloroform would answer the same purpose. 



:}: Flemming. " Beitrage zur Kenntniss der Zellc und ilirer Lebeaserscheinun- 

 gen." Arch. Mik. Anat., Vol. XX., p. i, 1881. 



