1 882.] in the Zoological Station in Naples. yjy 



be small and the color of the fluid begin to be a little lighter. It 

 is then allowed to cool, and filtered. To the filtered solution is 

 added a concentrated aqueous solution of picric acid (about four 

 volumes of the acid to one of the carmine solution). 1 



In order to protect this fluid against' changes attributed to 

 Bacteria by Hoyer, 2 Dr. Mayer places a small crystal of thymol in 

 the containing bottle; Professor Hoyer uses chloral-Jiydrate (i 

 per cent, or more) for the same purpose. 



4. Acetic Acid Carmine? — Pulverized carmine added to a small 

 quantity of boiling acetic acid (45 per cent.) until no more will 

 dissolve ; filtered and diluted to about I per cent, for use. 



Flemming used the concentrated solution. 



5. Grenadier's Carmine Solutions'— {1) Alum Carmine.— An 

 aqueous solution of alum (1-5 per cent., or any degree of concen- 

 tration) boiled with }4-l per cent, powdered carmine for 10-20 

 minutes; allowed to cool, then filtered. 



With the addition of a little carbolic acid the fluid will keep for 

 years. It colors quickly, and nuclei more strongly than other 

 parts. Objects washed in water after staining. 



(2) Acid Borax Carmine. — a. An aqueous solution of borax 

 (1-2 per cent.) and carmine {yi-}i per cent.) heated till the car- 

 mine is dissolved. 



b. Aceti 

 until the ( 



c Solution b left standing twenty-four hours, then turned off 

 and filtered. 



This solution, which is a modification of Schweigger-Seidel's 

 acid carmine, is not recommended for coloring in toto. It colors 

 sections in ^-3 minutes diffusely, and hence, after washing in 

 water, they are placed for a few minutes in alcohol (50 or 70 per 

 cent.) to which a drop of hydrochloric acid has been added ; then 

 transferred to pure alcohol. 



