MICROSCOPICAL DIAGNOSIS. 23 



can be purchased of any dealer in microscopical accessories for one 

 dollar an ounce. One ounce of this gelatine is dissolved in ten 

 ounces of water, and the mixture injected into the vessels while it 

 and the organ to be injected are both hot. Dr. Seiler prepares the 

 gelatine as follows: 

 Take of 



Best carmine, 2 drachms. 



Distilled water, 3 ounces. 



Strong liquor ammonia, 20 drops. 



Dissolve this and filter through cotton, covering the funnel 

 with a piece of glass plate, to prevent the evaporation of the ammo- 

 nia. The filtration is a somewhat tedious process, but is absolutely 

 necessary; the solution, however, will keep, and may therefore be 

 kept in stock. 



Then take of 



Cox's gelatine, 2 drachms. 



Distilled water, 2 ounces. 



Soak the gelatine in the water until it becomes soft, and then 

 dissolve it in a water bath and strain through fine flannel while hot. 

 Heat the gelatine solution again and add the carmine solution, and 

 bring the temperature up to about two hundred degrees, Fahrenheit. 

 Dilute acetic acid must then be added, drop by drop, under con- 

 stant stirring of the mixture, until the ammonia is just neutralized, 

 which is indicated by a sudden change of color in the solution, from 

 a lilac to scarlet. 



Dr. Seiler describes this process very minutely, and yet, in our 

 estimation, it is wiser economy for the busy worker to purchase it 

 rather than to make it. 



For a blue injecting mixture we have had the best success with 

 Beale's Prussian blue. In fact, could we be assured of a perfect 

 mixture, we should regard it as superior to. the carmine gelatine. 

 It penetrates the finest capillaries, and, if properly prepared, shows 

 no fine granules under the microscope. 

 It is made as follows: 



Best glycerine, 2 ounces, by measure. 



Muriated tincture of iron, 10 drops. 



Ferrocyanide of potassium, 3 grains. 



Strong hydrochloric acid, 3 drops. 



Water, i ounce. 



