120 ELEMENTARY TECHNOLOGY. 



Among the many stains proposed for B. tuberculosis, the 

 following from Pittion & Roux is commended by Dallinger: 

 Prepare three solutions. ' I. Ten parts fuchsin to 100 parts 

 absolute alcohol. 2. Three parts liquid ammonia to 100 dis- 

 tilled water. 3. Alcohol 50 parts, water 30, nitric acid 20 and 

 aniline green to saturation. Dissolve the green in the alcohol, 

 add the water, and lastly the acid. To 10 parts of sol. 2 add I 

 part sol. I and heat until vapor appears, then immerse the 

 cover glass with a drop of sputum which has been drawn over 

 another cover and dried quickly by passing through the 

 flame of a spirit lamp. After I minute wash with plenty of 

 water, rinse with distilled water and drop on the film side of 

 the cover a little of sol. 3. After about 40 seconds wash well, 

 dry, and mount in xylol balsam. 



Injection of vessels. 



By steady pressure on a syringe or the pipe of pressure 

 bottles so as to uniformly fill the vessels. 



1. With substances fluid at ordinary temperature. 



a. Aqueous solution of Prussian blue 2 per cent solution- 

 After injecting, the blue may be prevented from diffusing 

 through capillary walls by immersing in 90 per cent alcohol. 

 Mount in damar. 



b. Beale's Prussian blue in glycerine and water preserved 

 in acid glycerine. 



c. Solution of silver nitrate y 2 to I per cent for showing 

 cells of vascular wall. 



2. Substances solid at ordinary temperature. 



a. Carmine and gelatine. 



b. Prussian blue and gelatine. 



3. Opaque injections. Artists' colors rubbed up in ether, 

 or opaque colors in gelatine. 



p. Preservation of specimens. 



1. Dry mounting. On a slide with ring covered with 

 thin glass. 



2. In Canada balsam or dammar varnish (equal parts 

 dammar resin and gum mastic in benzole). The balsam may 

 be obtained dissolved in chloroform, benzole or xylol. Re- 



