70 



THE AMERICAN MONTHLY 



[April, 



taking negatives on paper which has 

 been perfected by the Eastmann Com- 

 pany, of Rochester. A holder car- 

 rying either twelve or twenty-four 

 paper plates is provided to fit any 

 camera. Full descriptions of the 

 apparatus are given in their circu- 

 lars, so that it is not necessary to 

 more than refer to it here. We can 

 say, however, that the paper nega- 

 tives are very convenient, and partic- 

 ularly desirable for field work, be- 

 cause of their lightness and compact 

 arrangement. 



[To be continued.^ 



Staiiiiiie Tissues in Microscopy. — 

 X. 



BY PROF. HANS GIERKE. 

 \^Coniinned from p. 5^.] 



19c;. Owsjaunikow. Ueber dieWirk- 



ing der Osmiamid verbindun- 



gen Fremy's auf thierische 



Gewebe. Melanges biol. tires 



du Bull de I'Acad. de St. 



Petersb., vii. 



Recommends Fremy's osmiamid 



verbindung i-iooo of water in place 



of perosmic acid. That has the same 



advantages as the latter, and is desti- 



tvite of the smell and injurious action 



on the skin. 



196. M. Schulze. Arch. mikr. 



Anat., vii, 180. 

 Potassium acetate is recommended 

 to mount preparations of osmic acid 

 in, for glycerin is seldom pure enough, 

 usuallv containing lead salts. Potass 

 acetate is used like glvcerin. 



197. Ranvier. Sur les elements con- 



jonctive de la moelle epiniere. 

 Gompt. Rend., Ixxvii, 1024. 

 A complete isolation of the nerves 

 of the spinal marrow occurs when 

 treated by a solution of perosmic acid 

 1-300 injected, and after some time 

 pressed out. 



1 98. Pouchet. De I'emploi des solu- 



tions concentrees d'acide os- 

 mique. Robin's Journ. de 

 I'Anat., 1876, p. 525. 

 Contains nothing new on osmic 

 acid. 



199. Broesicke. Die Ueberosmium- 



siiure in Verbindung mit Ox- 

 alsiiure a 1 s mikroskopisches 

 Farbemittel. Centralbl. f. d. 

 med. Wiss., 1878, No. 46, pp. 

 S33-836. 

 Fresh or recent material is laid for 

 an hour in a one per cent, pei^osmic 

 acid solution, then after washing in a 

 cold saturated solution of oxalic acid 

 for 24 hours, it may be exam- 

 ined in water or glycerin, but the two 

 should not be mixed. Mucin, cellu- 

 lose, amylum, bacteria, the outer 

 layer of fungi, the membrane of 

 Schw^ann, bony fibres and bones, 

 and the axis-cvlinder of nerves re- 

 main colorless. Intercellular sub- 

 stance, the cornea, walls of the capil- 

 laries, vitreous humor, and vitelline 

 membrane dye a crimson red. Mus- 

 cles, sinews, hyaline cartilage, and 

 other elements rich in albumen, stain 

 darker. The gray matter of nerves, 

 cell .protoplasm, and neuclei stain a 

 wine-red. 



200. Parker. On some applications 



of osmic acid to microscopic 



purposes. Journ. R. micr. 



Soc , ii, 381-383. 



Perosmic acid is recomniended for 



tender objects, as Crustacea, insects, 



plant tissues, etc., followed by the 



action of alcohol. 



OTHER METALLIC SALTS. 



201. Landois. Die impriignation der 



Gewebe mit Schwefelmetal- 



len. Centralbl. f. d. med. 



Wiss., 1865, No. 55. 



The tissues are first put in solutions 



of metallic salts, and when thoroughly 



soaked the metal is precipitated by 



dilute solutions of hydrogen sulphide, 



or ammonium sulphide, after careful 



washing. Salts of lead, iron, copper, 



platinum, and mercury give the best 



results. 



202. Polaillon. Etudes sur la texture 



des ganglions nerveux peri- 

 pheriques. Journ. de I'Anat. 

 et Phys., 1866, iii, 43. 

 The organs are hardened in a solu- 

 tion of ferric chloride, then thoroughly 

 w^ashed, and treated with tannic acid 



