CHARCOT-LEYDEN'S 



61 



CHLORIDE 



Charcot-Leyden's Crystals. Octahedral 



phosphate crystals found in stools of 

 persons infected with Endameba his- 

 tolytica and in a varietj^ of other condi- 

 tions. See description and illustration 

 hy Craig, p. 58. 



Cheese. Bacteria in, see Hucker, G. J., 

 N. y. Agric. Exp. Sta. Tech. Bull. 

 1921,87 (McClung, p. 147). 



Chicago Blue, see escape from venules after 

 intravenous injection (Smith, F. and 

 Rous, P., J. Exp. Med., 1931, 54, 499- 

 514). 



China Blue, see Anilin Blue. 



Chitin. 1. Method for softening of chitin in 

 formalin fixed insects (Murray, J. A., 

 J. Roy. Micr. Soc, 1937, 57, 15). Fix 

 primarily in 10% fornmlin in 0.8% aq. 

 sodium chloride, or indefinitely. Fix sec- 

 ondarily and dehydrate in equal parts 

 absolute alcohol, chloroform and glacial 

 acetic acid + corrosive sublimate to satu- 

 ration (about 4%). Warm together equal 

 parts chloral hydrate and phenol until 

 they fuse and form an oily liquid which is 

 fluid at room temperature. Leave speci- 

 mens in this 12-24 hrs. or longer. Clear 

 in chloroform, x3dol or carbon disul- 

 phide. Imbed in paraffin. 



2. Accordinsr to Hennings (sec Lee, 

 p. 597) fixation of insects in the following 

 mixture softens the chitin sufficiently 

 to permit the making of paraffin sections : 

 nitric acid, IC cc; 5% aq. chromic acid, 

 16 cc; sat. corrosive sublimate in 60% 

 alcohol, 24 cc; sat. aq. picric acid, 12 

 cc; and abs. ale, 42 cc. Fixation is 

 12-24 hrs. folio vred by washing in iodine 

 alcohol. An older method is to soften 

 chitin by treatment with a solution of 

 hypochlorite of soda (Lee, p. 249). 

 See Diaphanol, N. Butyl Alcohol, In- 

 sects, and Ticks. 



Chloral Hydrate, as a fi.xative for peripheral 

 nerves (Bank, E. W. and Davenport, 

 H. A. Stain Techn., 1940, 15, 9-14). 

 Chloral hydrate is also recommended as 

 a macerating medium for the separation 

 and isolation of epithelial and lining 

 cells by the Bensleys (p. 5). Accord- 

 ing to their instructions remove small 

 pieces alimeutar}' tract of pithed or 

 freshly killed frog and leave them in 

 5% aq. chloral hydrate 12-48 hrs. Then 

 tease with fine needles and examine. 

 See Cajal's chloral hvdrate method. 



Chlorazol Black E (CI, 581) of British Dye- 

 stuffs Corporation — Erie black G X 00 

 (National Aniline and Chemical Com- 

 pany) , Pontamine black E (I.E. Du Pont 

 deNemours & Co.) — an acid polj^-azo 

 dye. First described as a new biological 

 stain by Cannan (H. G., Nature, 1937, 

 139, 549). Review of its uses (Cannan, 

 H. G., J. Roy. Micr. Soc, 1941, 61, 

 88-94). As a vital dye (Baker, J. R., 

 Nature, 1941, 147, 744). Stains chro- 



matin black, cytoplasm greenish gray 

 after Zenker fixation (Darrow, M. A., 

 Stain Techn., 1940, 15, 67^8). As an 

 aceto-carmine auxiliary stain for chro- 

 mosomes (Nebel, B. R., Stain Techn., 

 1940, 15,69-72). 



Chlorazol Blue 3B, see Trypan Blue. 



Chlorazol Fast Pink used as anticoagulant 

 in experiments designed to influence 

 growth of transplants of lymphosar- 

 comas (Williams, W. L., Cancer Re- 

 search, 1946,6. 344-353). 



Chlorazol Pink Y, see Thiazine Red R. 



Chloride. In 1908 Macallum reviewed the 

 older literature and described his silver 

 test for chloride (Macallum, A. B., 

 Ergeb. d. Physiol., 1908, 7, 552-652). 

 The possibilitj', which has not yet been 

 finally answered, is that at some stage 

 in the technique there is a shift in the 

 position of chloride. The mere applica- 

 tion of the silver reagent may conceiv- 

 ably withdraw chloride from the cell. 

 For these reasons prior treatment of the 

 tissue by the Altmann-Gersh freezing 

 and drying method which reduces the 

 chance of movement of chloride to a 

 minimum is recommended. 



1. Gersh (Gersh, I., Anat. Rec, 1938, 

 70, 311-329) gives details of the proced- 

 ure on which the following instructions 

 are based. Tissues frozen in liquid air, 

 dried in vacuum, embedded in paraffin 

 and sectioned at 15m a-re mounted near 

 one edge on chemically clean large cover 

 slips by simply pi'essing down with a 

 finger, just melting over a flame and 

 pressing down again. Immerse cover- 

 slips with attached sections in anhydrous 

 petroleum ether (b.p. 20-40°C.) freshly 

 distilled over sodium in a watch glass 

 covered by another at all times except 

 during actual manipulations. This re- 

 moves the paraffin. Remove and burn 

 off the ether quickly by a flame and allow 

 to cool to room temperature. Then treat 

 two coverslips with attached sections 

 differently. 



A. Cover for few seconds with drop 

 of 60% aq. silver nitrate diluted with 

 sufficient quantity of cone phosphoric 

 acid to prevent precipitation of rather 

 large concentrations of phosphates and 

 then saturate with silver chloride. After 

 filtering 2-3 drops aq. dest. are added to 

 every 10 cc. before using. 



B. Cover similarly with: 60% aq. 

 silver nitrate saturated with silver phos- 

 phate and silver chloride and dilute 

 after filtering in the same way. 



Decant fluids from both coverslips. 

 Add to each 1 drop chemically pure 

 glycerin and mount with section plus 

 glycerin down on chemically clean slides. 

 Expose both to carbon arc radiation for 

 same length of time but at a distance 

 not to warm the specimens. Examine 



