158 COLLODION AND OTHEK IMBEDDING METHODS. 



CHAPTER XVI. 

 COLLODION (CELLOIDIN) AND OTHER IMBEDDING METHODS. 



290. Collodion or Celloidin. The collodion method is due to 

 DUVAL (Journ. de I'Anat., 1879, p. 185). Celloidin, recom- 

 mended later on by MERKEL and SCHIEFPEEDECKEE (Arch. f. 

 Anat. u. Phys., 1882, p. 200), is merely a patent collodion. 



It is stated to be a preparation of pure pyroxylin, and is 

 patented for Germany and England under the name of 

 " Schering's Celloidin. " It is manufactured by the Chemische 

 Fabrik auf Actien (vorm. E. Schering), Berlin, N. Fenstrasse, 

 11, 12. It may be obtained through the post by writing to 

 Schering's Grime Apotheke, Wittick and Benkendorf, 

 Berlin, N. Chaussee-Strasse, No. 19, or from Griibler, or the 

 other dealers in histological reagents. 



It is stated to be prepared with the purest pyroxylin, and 

 to be always pf a uniform composition. It is sent in the form 

 of tablets of a tough, gelatinous consistency, and slightly 

 milky-white transparency. These tablets have exactly the 

 consistency that is required for section-cutting. They contain 

 20 per cent, of pure pyroxylin. Celloidin is entirely soluble, 

 in all proportions, in ether and alcohol. It is free from acids. 

 It is not detonant. If ignited it burns like paper ; heated in 

 a test-tube it carbonises without exploding. 



In order to make a 2 per cent, collodion, take one tablet of 

 celloidin (which contains 40 grammes of the dry pyroxylin) 

 and such a quantity of alcohol and ether that the whole shall 

 weigh 2000 grammes. For a 3 per cent, collodion you take 

 such a quantity of alcohol and ether that the whole shall wei^'li 

 1333 grammes; and for a 4 per cent, collodion such a quan- 

 tity that the whole shall weigh 1000 grammes. The relative 

 portions of alcohol and ether may be taken according to dis- 



