144 



THE AMERICAN MONTHLY 



[August, 



which I am at present engaged 

 with Dr. Klein. 



There is one point which greatly 

 facilitates a good result with this 

 process — that is, after staining the 

 sections in picrocarmine to place 

 them in plain water acidulated with 

 a few drops of acetic or picric acid 

 for an hour before staining with 

 logwood ; they take the second stain 

 better and do not fade afterwards. 



The next process consists of — 



1. A solution of carmine and 

 borax. 



2. A mixture of hydrochloric 

 acid and absolute alcohol. 



3. A solution of indigo-carmine. 

 The carmine solution is prepared 



by mixing 



Carmine, . . . half drachm 

 Borax, . . . two drachms 

 ^Vqua, .... two ounces 

 and pouring oft" the clear fluid. It 

 must not be filtered. Three or four 

 drops of this solution are placed in 

 a watch-glass, and the sections im- 

 mersed for a few minutes ; they are 

 then removed to a mixture of hy- 

 drochloric acid and absolute alcohol, 

 one part of the acid to twenty parts 

 of alcohol, and. allowed to remain 

 there until they take on a bright 

 rose color ; this happens in a few 

 seconds. They must then be 

 washed in methylated spirit several 

 times to remove the acid, when 

 they will be ready for staining with 

 the indigo-carmine, which is pre- 

 pared in the following manner : 



A saturated solution of indigo- 

 carmine is made in distilled water 

 and Altered ; a portion of this solu- 

 tion is then added to some methy- 

 lated spirit until it has attained a 

 moderately deep-blue color; this 

 must then be filtered to remove the 

 coloring matter, a good deal of 

 which is precipitated ; it wiU then 

 be tit for use. 



A small quantity is placed in a 

 watch-fflass, and the sections al- 



lowed to remain until they have a 

 distinctly blue color. 



I have found this process very 

 useful in pathological investigation, 

 especially in the Ckrcinomata ; and 

 in specimens hardened in chromic 

 acid it does away with the tedious 

 process of passing them through a 

 solution of bicarbonate of soda. 



This method is modified from 

 one mentioned iii the American 

 Quarterly Microscopical Journal 

 by Dr. Seller. 



I next come to the anilines ; and 

 of these, after a large number of 

 experiments, I have found roseine, 

 aniline violet, aniline blue, and 

 iodine green, give the most satis- 

 factory results. The principle I 

 worked on was to make a spirituous 

 solution of one color and a watery 

 solution of another, and in this way 

 I could depend on the result. 



I made solutions of roseine and 

 aniline violet in spirit, and of ani- 

 line blue and iodine green in dis- 

 tilled water. A few drops of one 

 of the spirit solutions being placed 

 in a watch-glass and diluted with 

 spirit, the sections were immersed 

 for a short time (this will depend 

 on the strength of the solution and 

 the tissue itself, as some stain more 

 quickly than others) ; they ought to 

 be taken out of the stain and exam- 

 ined in clean spirit, and a little 

 practice will soon show when they 

 are stained enough. They are then 

 washed in methylated spirit until 

 no more color comes away from 

 them. A little of the aqueous 

 solution is now placed in a watch- 

 glass and diluted, the section is re- 

 moved from the spirit to it; the 

 spirit causes the section to spread 

 itself out and float on the watery 

 solution, and it may be seen taking 

 on the new color. For a light stain 

 this is sufficient, and it need not be 

 wholly immersed. It is then well 

 washed in plain water and placed 



