170 Animal Micrology 



This is an excellent reagent for embryos, either for entire 

 mounts or for sectioning. Chick embryos of 24 to 48 hours 

 should remain in the liquid for from 2 to 4 hours; older embryos, 

 for from 3 to 6 hours. For washing, 70 per cent, alcohol is used. 

 It should be changed (frequently at first) until the color ceases 

 to come out of the embryos. Preserve in about 80 per cent, 

 alcohol. 



Lillie recommends the addition of glacial acetic acid sufficient 

 to make a 5 per cent, solution of acetic acid. The reagent, as 

 thus modified, certainly gives beautiful results. For staining, 

 use Conklin's picro-hematoxylin (48). 



26. Platino-Aceto-Osmic Mixture (Hermann's fluid). 

 Platinum chloride, 1 per cent, aqueous solution 60 c.c. 

 Osmic acid, 2 per cent, aqueous solution . . 8 c.c. 

 Glacial acetic acid 4 c.c. 



Hermann's fluid is one of the most valuable cytological re- 

 agents. Only small pieces of tissue should be used. The washing 

 and subsequent treatment are the same as for Flemming's solution 

 (11). For subsequent treatment with pyrogallol, see 64. Read, 

 also, remarks on osmic acid (20). 



RabPs Picro-Sublimate, see 24. 



Rath's (0. vom) Picro-Sublimate, see 24. 



Ripart and Petit, Liquid of, see 9. 



Tellyesnicky's Fluid, see 5. 



Worcester's Fluid, see 19. 



Zenker's Fluid, see 6. 



II. STAINS 

 Read the general statement about stains in chap ii. 



27. Alum Cochineal. 



Potassic alum . 6 grams 



Powdered cochineal 6 grams 



Distilled water 90 c.c. 



Boil for half an hour; after the fluid has settled, decant the 

 supernatant liquid, add more water to it, and boil it down until 

 only 90 c.c. of the decoction remains. Filter when cool, and add 

 a bit of thymol or a little salicylic acid to prevent the growth of 



