137 



capillaries well. Veins and arteries side by side may be found in 

 the mesentery. If the brain vessels are injected one can get admir- 

 able preparations showing nuclei as well as cell outline by staining 

 in hematoxylin. Mount in glycerin, or, if desired, dehydrate and 

 mount in balsam. The tissue may be kept in 50% alcohol or in 

 50% glycerin for several months before mounting if it is kept in the 

 dark. 



For large vessels and endocardial epithelium open the vessels 

 or the heart and silver as directed above for mesentery. It may be 

 necessary to make thin free-hand sections so that the preparation 

 will be thin enough for high powers. 



FORMUlvAS. 



In addition to those given elsewhere; see also The Microscope, 7th ed., 

 l\ 297-316. 



I 149. Acid alcohol. 95% alcohol, 100 c.c. ; hydrochloric acid, t\, c.c. 

 For Hcl carmine, use 95% alcohol, 100 c.c. ; hydrochloric acid, ]i. c.c. 



\ 150. Alcohol, (i) 67%. Take 959^ alcohol, 2 parts; water, i part. 

 (2) 82%. Take 95% alcohol, 5 parts ; water, i part. 



I 151. Clarifier. (Castor-xylene). Castor oil, i part; xylene, 3 parts. 



\ 152. Clearer. (Carbol-xylene). Melted carbolic acid crystals, i part 

 (by volume) ; xylene, 3 parts. 



I 153. Normal salt solution. NaCl. (common salt), .6 gram; distilled 

 water, 100 c.c. 



\ 154. Collodion, (i) Thick collodion, 8% solution. Ether-alcohol, 100 

 c.c. ; soluble cotton, 8 grams. (2) 6% solution. Ether-alcohol, 100 c.c. ; sol- 

 uble cotton, 6 grams. (3) Thin collodion, Jj4%, ether-alcohol, 100 c.c. ; solu- 

 ble cotton, 1)4 grams. 



I 155. Ether-alcohol. Sulphuric ether, i part ; 95% alcohol, i part. 

 « \ 156. Glycerin, eosin and alum carmine. Glycerin, 85 c.c. ; alum car- 

 mine, tYz c.c. ; %% aq. sol. eosin, 7^ c.c. 



\ 157. Latnpblack m,ixture. Lampblack, i gram ; gum arable, 1 gram ; 

 common salt, -f^ gram ; water, 20 c.c. 



'i 158. Neutral (^alkaline) balsam.. Canada balsam is liable to be slightly 

 acid. This is of advantage for mounting sections stained with carmine or with 

 acid fuchsin (as when picro-fuchsin is used), and for injected preparations 

 where carmine or Berlin blue is used as the coloring matter. For hematoxylin 

 and other stains easily affected by acid media it is often advantageous to use 

 neutral or slightly alkaline balsam as a mounting medium. To obtain this 

 slightly alkaline balsam, add some pure sodium carbonate to the thin xylene 

 balsam and shake thoroughly at intervals for a day or so. Allow the balsam to 

 stand until the soda has settled, then decant and thicken by evaporation till of 

 the desired consistency. ( The Microscope, 7th ed., p. 176, \ 300). 



