136 naturalists' assistant. 



solve only a portion of the resulting powder. Let the solution stand 

 several days until it becomes saturated and assumes a dark violet color. 

 If still too red add more alum. Then filter and dilute with one-fourth 

 of seventy-five per cent, alcohol. 

 Haimatoxylin (No. 2). 



Ground Campeachy wood I oz. 



Pulverized alum 2 oz. 



Mix and triturate in a mortar for twenty minutes; then add two 

 ounces of hot aistilled water, and let the whole stand a couple of days. 

 Filter and add to each ounce a quarter of an ounce of ordinary alco- 

 hol. After standing twenty-four hours more, filter again to remove the 

 precipitated alum. This will keep two months in a well stoppered vial. 

 Hematoxylin. (No. 3). 



Hsematoxylin crystals 35 parts. 



Absolute alcohol 1000 parts. 



Water (distilled) 3000 parts. 



Alum 10 parts. 



Dissolve the hzematoxylin in the alcohol, the alum in the water and 

 mix. The mixture is purple at first, but gradually turns blue. It can 

 however be used at once after filtering. 

 Hcematoxylin (Kleinenberg's Method). 



Make a saturated solution of crystallized chloride of calcium in 70 

 per cent, alcohol, and add alum until no more will be dissolved. This 

 is the first solution; the second is a saturated solution of alum in 70 per 

 cent, alcohol. Mix these two solutions in the proportions one of the 

 first to eight of the second. Then to the mixture add a few drops of a 

 saturated solution of crystallized haimatoxylin in absolute alcohol. 



Frey's Fuschine solution. 



Crystallized fuschine i centigramme. 



Absolute alcohol 15-20 drops. 



Distilled water 15 cu. centimetres. 



This, though a useful staining medium, possesses the disadvantage that 

 it cannot be used where the tissue is to be mounted in balsam. 



