310 proceedings of societies. 



Medical Miceoscopical Society. 



20th March, 1874. 



Staining with Aniline Dyes for Balsam Mounting. — Mr. George 

 Gibbs read a paper on this subject, which he was first led to study 

 from reading the following passage in Frey's 'The Microscope:' 

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

 auiliue red], 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 perfectly preserved when the specimen was mounted 

 in Canada balsam. 



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

 precipitating the colouring matter ; but should this occur, brush- 

 ing with a camel's hair pencil would remove the deposit. Mr. 

 Gibbs claimed three advantages for this method : — 1st. Its 

 cleanliness. 2nd. That one has the most perfect control over the 

 depth of colour obtained by regulating 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 Frey's aqueous solution of aniline, the nerve-fibres of the 

 spinal cord as well as the nuclei of cells being vividly brought 

 out. 



Staining with Picro-carminate of Ammonia. — The Secretary read 

 Dr. E. Cresswell Baber's paper upon this subject, which is pub- 

 lished in extenso in the present number of the Journal. 



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. 

 Keferred to Frei's methods if employing pico-carmiue ; had ob- 

 tained good results from first staining in carmine, and subse- 

 quently 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 witli 

 logwood, and then with picric acid, showed the yellow centres of 

 the " birds' nests" described by Mr. Baber, while the surrounding 

 parts were tinted by the hsematoxylin. Had only used carmine 

 and picric acid as separate solutions, but by this means had seen 

 yellow channels of communication from one bird's nest to 

 another. 



Mr. Kesteven asked if aniline dyes were permanent. 



Mr. Atkinson found that crystallized magenta, when first used 

 for staining sections became blue, and then after a time disap- 



