THE MICROSCOPE. 153 



m alcohol unequally and thus are apt to spoil the right proportion 

 of the specimen. 



To insure perfect success in staining it tn toto (one of the 

 principal advantages of the method) the alcohol must be changed 

 as .often as it becomes yellow, for the specimen is not ready for 

 Staining, until the alcohol remains perfectly colorless. The speci- 

 men is then removed to the staining fluid, which is as follows: 

 Dissolve five grammes of best carmine in about eight grammes of 

 caustic ammonia, then add distilled water until its contents equal 

 100 cubic centimetres. After equal parts of absolute alcohol and 

 glycerine are added to it, it is put on the hot water bath and kept 

 there, until the prevailing- odor of the ammonia Las almost disap- 

 peared, which is usually accomplished in about two hours. When 

 properly made, no sediment will be deposited. The fluid is now 

 ready for use and has this great advantage over other carmine solu- 

 tions, that it can be used over and over again and at the same time 

 acts as a preserving fluid, so that the specimen can be left in it for 

 an unlimited time. It never stains too deep a shade and makes the 

 nuclei come out very sharp. For the exanjination of glands, where 

 it brings out the lunulas most perfectly and also of nervous matter, 

 it cannot be surpassed. The disagreeable quality of carmine — to 

 stain well one day and diffuse the next — is thereby entirely obviated. 

 Another staining fluid, with which you can obtain beautiful results 

 either in combination with the first for double staining or by itseff 

 alone, is that prepared with haematoxylin. It is especially to be 

 recommended for pathological specimens, because the haematoxy- 

 lin has a peculiar affinity to the products of inflammation and cells 

 of pathological origin. To prepare this fluid mix Boshmer's haema- 

 toxylin with equal volume parts of absolute alcohol and glycerine. 

 Thus mixed it forms the solution for staining in toto. It 

 does not stain so quickly as the carmine solution and 

 pieces of the above mentioned size must remain in it from three to 

 four weeks, when they are taken out and again put into alcohol to 

 harden. 



Specimens stained in the carmine solution alone are taken out 

 and to remove the superfluous carmine, are washed in distilled water 

 for a few hours, then put into weak alcohol to be changed for 

 stronger, until no more of the pink coloring matter is drav/n from 

 the specimens; then to extract all water from the tissue it is trans- 



