THE MICROSCOPE. 109 
LOGWOOD STAINING SOLUTION. 
HENEAGE GIBBES, M. D., 
PROFESSOR OF PATHOLOGY IN THE UNIVERSITY OF MICHIGAN. 
OGWOOD stain has been made in various ways, both from the 
extract and from the coloring matter Hematoxylin, but there 
has always been a difficulty in keeping the solution at the same 
strength. The coloring matter deposits on the side of the bottle, and 
after a time the stain is useless. Another drawback I have found in 
the different action of various extracts, presumably from some adul- 
teration they contain. 
The logwood solution I used for years was made from extract, 
with three times the amount of alum added. With some extracts 
this solution was ready for use in three weeks ; with others, not for 
three months. As I had to prepare this stain for the use of large 
classes, it was often a serious matter having to wait so long, and after 
trying every extract in the market and finding they all had the same 
defects in varying degrees, I commenced a series of experiments with 
logwood chips, with the result that I have found in the following 
formula all that could be desired in a Logwood Stain. 
I find the best chips to use are those having a tawny color and 
not too small. 
Take of 
hoewoode Chips. s-, = oscin.2s «Segee- vase rece Lia} 
Distilled eVwWiaterse ses ws ees fee oe ote 50 oz. 
Mix in porcelain lined saucepan or granite iron kettle and heat 
slowly to the boiling point. 
Boil for ten minutes, and while boiling stir with a glass rod 
and add very slowly from $ to 1 oz. of potash alum. 
The addition of the alum instantly turns the color almost black 
and only sufficient alum is required to do this. The amount varies 
with different samples of chips. 
After the alum is added and the mixture has boiled for ten 
minutes set it aside for twenty-four hours. 
Then filter and add four ounces of alcohol to make it keep. 
If properly made it will be ready for use at once. 
This Logwood Staining Solution has the following characters 
to recommend it : 
It is inexpensive. 
It is easily made. 
It is ready for use at once. 
It will not deposit on the sides of the bottle. 
Ann ARBor. 
