CRYOSTAT 



91 



CURTIS' SUBSTITUTE 



water 10 min. Stain for 1 min. or more 

 in: acid fuchsin (C.C.), 1 gm.; orange 

 G (CO.), 0.4 gm.; aq. dest., 300 cc; 

 thymol, 0.2 gm.; glacial acetic acid, 3 

 cc. Rinse in aq. dest. Decolorize in 

 fresh 1% aq. phosphotimgstic or phos- 

 phomolybdic acid until arterial media 

 is red and adventitia is colorless. Rinse 

 very quickly in aq. dest. Counterstain 

 in 2% aq. anilin blue, W.S. (CC.) 

 100 cc. + glacial acetic acid, 2 cc. or in 

 1% aq. light green SF yellowish (CC.) 

 100 cc. + glacial acetic acid, 1 cc. Rinse 

 in aq. dest. Decolorize in 1% acetic 

 acid under microscope. Rinse in aq. 

 dest. Dehydrate in 3 changes abs. ale. 

 Clear in 3 changes .xylol and mount. 

 Like original method but nuclei brown or 

 black and collagen blue or green de- 

 pending on counterstain. 



Cryostat. Written by Dr. Gordon H. Scott, 

 Dept. of Anatomy, Wayne University, 

 School of Medicine, Detroit, Mich. — 

 This apparatus is one which is designed 

 to dehydrate tissues at low tempera- 

 tures. A detailed description has been 

 given by Packer and Scott (J. Tech. 

 Methods, 1942, 22, 85-96) and by Hoerr 

 and Scott (Medical Physics, Otto Glas- 

 ser, 1944, Year Book Publishers). Tis- 

 sues frozen in liquid air or nitrogen are 

 placed in a chamber which is connected 

 with a fast pumping vacuum system. 

 Water vapor which is released from the 

 tissues is trapped by P2O5 as well as by 

 a cold trap. In the Packer-Scott ap- 

 paratus the relative amount of water 

 vapor in the system is determined by 

 its flow past a spaced pair of ionization 

 gauges between which is placed the 

 P2O5 trap. When these gauges are in 

 balance it is assumed water vapor is no 

 longer being released in quantity, and 

 therefore the tissues are dry. As soon 

 as the tissues, placed on a container 

 of solid out-gassed paraffin, are dry, 

 the paraffin is melted and the tissues 

 are infiltrated. This latter procedure 

 is accomplished without the necessity 

 of breaking the vacuum. This small 

 but important step provides tissues 

 which have been frozen-dried and pre- 

 pared for cutting without their having 

 been partially rehydrated by exposure 

 to air at ambient pressure and temper- 

 ature. See Altmann-Gersh frozen de- 

 hydration method. 



Cryptococcus Hominis, see Blastomycosis. 



Cryptosporidium, see Coccidia. 



Crystal Violet as vital stain for fibroblast 

 nuclei (Bank, O. and Kleinzeller, A., 

 Arch. exp. Zellforsch., 1938, 21, 394- 

 399). See Anilin Crystal Violet and 

 Gentian Violet. 



Crystal Violet-Acid Fuchsin. This is one 

 of R. R. Bensley's neutral stains espe- 



cially advocated for the demonstration 

 of secretion antecedents in gland cells. 

 The technique is described by the 

 Bensleys (p. 97). To make stain add 

 filtered sat. aq. acid fuchsin to similar 

 solution crystal violet until precipita- 

 tion is complete. Collect ppt. on fdter 

 paper, wash through once with aq. dest. 

 Dry and dissolve in absolute alcohol to 

 saturation. For staining add 5 cc. of 

 above stock solution to 45 cc. 20% 

 alcohol made from absolute. In this 

 color paraffin sections of Formalin- 

 Zenker fixed material for 5 min. Blot 

 with filter paper in one hand and add 

 with other hand absolute alcohol from 

 a pipette, flood with absolute. Blot 

 immediately. Add few drops clove oil. 

 When differentiation, observed under 

 microscope, is optimum transfer to 

 pure benzol and mount in balsam. 



Crystal Violet and Alizarin, see Benda's 

 Method for Mitochondria. 



Crystals. These are encountered in many 

 forms, see Charcot-Leyden, Ice, Sul- 

 fonamides, Hemin, Florence, Virchow's, 

 Spermin, Lubarsch, Neumann's, Teich- 

 mann's, Mineral residue of Microincin- 

 eration, Polarization Optical methods. 

 Numerous Microchemical Reactions 

 especially for minerals, yield crystal- 

 line materials. Fat crystals are often 

 distinctive as for beef, duck, lard, etc. 

 (Schneider, A. The Microbiology and 

 Microanalysis of Foods. Philadelphia: 

 P. Blakiston's Son & Co., 1920, 262 pp.) . 

 Study of crystals is really a problem for 

 experts. For the best techniques con- 

 sult Section I on "Identification" in 

 Bunn, C. W., Chemical Crj^stallog- 

 raphy, Oxford University Press, 1946, 

 234 pp. Comparison of the crystals to 

 be diagnosed with some of the 234 

 figures in the book may result in prompt 

 recognition. 



Culture Media, see Bacteria, Leishmania, 

 Protozoa, Tissue Culture, Trypano- 

 somes, NNN Medium. 



Curcumine, see Brilliant Yellow. 



Curettings, gelatin method for rapid frozen 

 sections of (Meeker, L. II., J. Techn. 

 Meth. & Bull. Int. Assoc. Med. Mu- 

 seums, 1936, 16, 41-42). 



Curtis' Substitute for Van Gieson stain as 

 modified by Leach, E. H., Stain Techn., 

 1946, 21, 107-110. Use any desired 

 fixative. Bring sections to water and 

 treat with iodine and hypo (sodium 

 thiosulfate) if necessary. Stain for 5- 

 10 min. in Weigort's hematoxylin. To 

 make this mix (just before use) 1 part 1% 

 hematoxylin in absolute alcohol with 



1 part of mixture containing 30% aq. 

 ferric chloride 4 cc, cone, hydrochloric 

 acid, 1 cc. 2% acetic acid 100 cc. and add 



2 parts aq. dest. Wash for 5 min. in 



