35° ANATOMY OF THE DOMESTIC FOWL 



2. Pass the specimen through each of the following solutions, 

 leaving it in each twenty-four hours or until the normal color is 

 obtained. The specimen should be removed from alcohol as soon 

 as color is attained. If it is left in the alcohol too long it will 

 again lose some of its color. 



Alcohol 40 per cent. 



Alcohol 60 per cent. 



Alcohol 80 per cent. 



Alcohol full strength 



3. Place the specimen in the following permanent solution, label, 

 and place in museum. 



Glycerin 40 c.c. 



Potassium acetate 40 grams 



Distilled water , . . . . 400 c.c. 



A small piece of thymol must be placed on the top of the liquid 

 in each jar, or mold wiU develop and spoil the specimen. 



To Make Specimens Transparent. — Specimens may be rendered 

 transparent by the method of Spalteholz. 



The steps are essentially as follows: 



I. Preparation of the fresh tissue. If any parts are to be made 

 conspicuous, as blood-vessels, or the lymphatic system, they must 

 be injected with an insoluble, unbleachable substance. Spalteholz 

 recommended carmine or methylene blue, and carbon. I have 

 found Higgin's ordinary black carbon ink excellent for this purpose. 

 The system or systems are injected with this substance while the 

 tissue is perfectly fresh. 



II. Fixation. The tissues are fixed preferably in 10 per cent, 

 formalin. The length of time for fixation depends on the size of 

 the tissue. In formalin it requires from eight hours upward to fix 

 completely. 



III. Rinsing. Running tap water for five or ten minutes accom- 

 pUshes the rinsing. If it is impracticable to pass directly into the 

 bleaching fluid, the tissues may be kept temporarily in 60 per cent, 

 or 70 per cent, alcohol. They should then be rinsed again thoroughly 

 in water when ready to bleach. 



IV. Bleaching. The bleaching fluid used is hydrogen peroxid 

 to which ammonia is added until a white precipitate forms. The 

 proportion is approximately two parts of peroxid and one of 

 ammonia. The material is bleached until all the color is removed 



