THE MICROSCOPE. 165 



bottle and become filled with granules and frequently with 

 threads. 



As so many changes are due to living ferments (organized fer- 

 ments, as bacteria, yeast-like fungi, etc.), it occurred to the 

 writer that the deterioration of the hematoxylin might be due, 

 wholly or in part, to one or more of these organized ferments. 

 If this supposition is correct, any ferments accidentally present 

 in the water and alum used, should be destroyed. If then some 

 substance is added to the solution to prevent the development 

 of germs that might subsequently get into the solution, the so- 

 lution would be likely to be lasting and to retain its excellence. 

 Experiments proved the accuracy of the hypothesis. An aque- 

 ous solution of hematoxylin prepared as directed below and 

 made nearly a year previous to the present writing is still in ex- 

 cellent condition. During the'year it has been in the laboratory 

 and subjected to all the vicissitudes of heat, dust, light, and all 

 the other conditions that an ordinary histological re-agent must 

 endure. It has remained in the same bottle all the time, and 

 now, after nearly a year, there is no deposit on the bottle, and 

 the stain acts as well as in the beginning. 



Formula : 



Distilled water 200 cc. 



Potash or ammonia alum 7^ grams. 



Chloral hydrate 4 



grams. 



Hematoxylin crystals .. 1-10 gram. 



To prepare the solution, place the water and alum in an agate 

 or porcelain vessel and boil for five minutes or more, preferably 

 fifteen or twenty minutes if the water is not freshly distilled. 

 This boiling will destroy any germs in the water or alum. Al- 

 low the boiled alum solution to cool, and add sufficient freshly 

 boiled distilled water to compensate for evaporation and make 

 200 cc. of alum water. Add the chloral hydrate and dissolve 

 the hematoxylin crystals in 10 cc. of 95 per cent alcohol and 

 add to the mixture. 



At first the color will be rather faint, but after a week or two 

 it will become a deep purple. The deepening of the color is 

 more rapid if the bottle is left uncorked in the light and is 

 shaken occasionally. 



If the stain is too concentrated it may be diluted with freshly 

 distilled water or with a mixture of water, alum, and chloral. 



