48 PROCEEDINGS OF SOCIETIES. 



Medical Microscopical Society. 



The twelfth meeting of this Society was held on Friday, March 

 20th, at the Eoyal Westminster Ophthalmic Hospital, Jabez Hogg, 

 Esq., President, in the chair. 



The minutes of the last meeting having been read and confirmed, 

 Mr. George Giles read a paper " On Staining with Aniline Dyes for 

 Balsam Mounting." 



The author of the paper was first led to study this subject from 

 reading the following passage in Frei's 'Technology' : — 



"It is very unfortunate that alcohol soon extracts the colour [of 

 aniline-red J, so that it is impossible to preserve the specimen in 

 Canada balsam." 



To obviate this inconvenience he tried a 2 per cent, solution of 

 aniline in spirit, and then found that by staining sections that had 

 been in spirit with this solution for three or four minutes, rinsing in 

 spirit and placing subsequently in oil of cloves, the colour was jier- 

 fectly preserved when the specimen was mounted in Canada balsam. 

 Oil of cloves was preferable to turpentine, the latter at times pre- 

 cijjitating the colouring matter; but should this occiu', brushiug with 

 a camel's hair pencil would remove the deposit. Mr. Giles claimed 

 three advantages for this method : 1st, Its cleanliness ; 2nd, That one 

 has the most jierfect control over the depth of colour obtained by re- 

 gulating the time of the subsequent washing in spirit ; 3rd, That the 

 colour is less trying to the eyes than that of carmine. Its selective 

 power was greater than that of Frei's aqueous solution of aniline. The 

 nerve fibres of the spinal cord, as well as the nuclei of cells, being 

 vividly brought out. 



The Secretary then read a paper by Mr. E. C. Baber — who was 

 unavoidably absent — upon " Staining with Picro - Carminate of 

 Ammonia." 



Peeparation of Picko-Carmine. 



Pure Carmine 1 grme. 



Liq. AmmonisQ 4 c. centres. 



Water 200 grmes. 



INIix ; and then add 



Picric acid 5 grmes. 



Agitate from time to time during two daj^s; allow risidue to settle; decant and 

 evaporate decanted liquor at the temperature of Ike air; redissolve the crystals iu 

 •water (strength, 2 p. c); and filter if necessary. 



In the discussion that followed, — 



Dr. Matthews remarked that some tissues attract red rather than 

 purple colours : thus, nuclei generally were more easily stained by the 

 former. Judson's dyes he had found useful. Eeferred to Frei's 

 methods of employing picro-carmine ; had obtained good results from 

 first staining in carmine, and subsequently in a solution of picric acid. 

 He had found Stevens' writing fluid a ready and useful stain for 

 sections. 



Mr. White had found a section of epithelioma, stained with log- 



