1897] MICROSCOPICAL JOURNAL. 65 



Further, material preserved in such a solution is better 

 adapted for subsequent microscopic examination, since 

 the protoplasm of the cell is less altered and the nucleus 

 stained better and deeply. 



The method he adopts is as follows: — The material must 

 not be too long- washed in water, and should be left in the 

 formalin for a period depending- on size and thickness. A 

 kidney or spleen requires two days' immersion and the so- 

 lution should be chang-ed until it no long-er g-ives a dirty 

 brownish red color. Care must be taken to bring- all por- 

 tions of the object into contact with the solution, and the 

 object must be g-iven the color it is to retain permanently, 

 since the formalin solution causes it to assume a consist- 

 ency such that its shape cannot afterwards be modified. 

 In the formalin solution the org-ans chang-e color and be- 

 come of a dirty bluish grey. On placing- them in ninety- 

 five per cent alcohol the normal color returns. Before 

 permanently placing- the org-an in alcohol it must be washed 

 in alcohol until the latter no long-er becomes cloudy. The 

 material must not be washed with water; it is left in alco- 

 hol until the normal color returns; if left long-er the alco- 

 hol removes the color. For a kidney or spleen, twenty-four 

 hours will be sufficient. The permanent preserving- fluid 

 is equal parts g-lycerine and water; the material floats at 

 first but sinks later ; the color is now at its best, after a 

 little while the fluid becomes yellowish and wants renewal. 

 Tissues so preserved have not underg-one the slig-htest 

 alteration in nine months. 



The method is not applicable to other color than blood. — 

 Int. Med. Mag-azine. 



Infiltrating Dental and Osseous Tissues for Microscop- 

 ical Work. — At a recent meeting of the Odontolog^ical So- 

 ciety of Great Britain Mr. Charters White g-ave the details 

 of the method he adopts to demonstrate the presence of 

 spaces in hard sections of dental and osseous tissues. The 

 section to be treated must be g-round moderately thin, to 

 about 1-32 in , and then immersed in absolute alcohol for 

 five minutes, and subsequently in ether for a similar per- 

 iod. It is next transferred to a thin solution of celloidin 



