CARMINE-GELATIN 



54 



CARTILAGE 



20% carmine and 50% gelatin (Bensley, 

 R. R., personal communication to Dr. 

 R. A. Knouff). 2. Triturate 40 gms. 

 carmine Merck: NFIV with 40 cc. strong 

 ammonia and add water to 200 cc. After 

 standing 24 hrs. filter through paper. 

 Boil filtrate down to 100 cc, add water 

 to 200 cc. and repeat. Add 70 gms. 

 gelatin dissolved in water and make up 

 with water to 1 liter (MacCallum, D. B., 

 Am. J. Anat., 1926, 38, 153-175). 



Carnoy-Lebrun fixative for insects and ticks. 

 Equal parts chloroform, absolute alcohol 

 and acetic acid saturated with mercuric 

 chloride. See Slifer-King Method. 



Carney's Fluid in abs. ale, 6 parts; chloro- 

 form, 3 parts; and glacial acetic acid, 1 

 part. Also known as Van Gehuchten's 

 mixture. A very quick fixative. Do 

 not wash in water but in 95% ale. It is 

 employed for many purposes. See 

 Fibrin, Foot's Method, Glycogen Neu- 

 rofibrils. 



Carotin, put green leaves in sat. aq. KOH, 

 1 part ; 40% ethyl alcohol, 2 parts and tap 

 water 3 parts in wide mouthed bottle 

 with tight glass stopper to prevent ab- 

 sorption of CO2 from air or seal with 

 vaseline. Keep several days in dark 

 until tissue is yellow and fluid is green. 

 Change pieces to aq. dest. several hours. 

 Remove small pieces, dry on slide with 

 filter paper. Add 1 drop cone. H2SO4. 

 It turns green, then blue. Under micro- 

 scope carotin crystals appear dark blue 

 (Steiger, A., Microkosmos, 1941, 8, 

 121-122). Carotin is a precursor of 

 Vitamin A. 



Carotinalbumins. Combinations of caro- 

 tinoid pigments with protein. Rather 

 uncommon. As an example Lison (p. 

 245) cites the blue carotinalbumin in 

 the carapace of the lobster which on 

 boiling is split into a protein and a red 

 carotinoid. 



Carotinoids. Pigments which are non- 

 saturated and nonnitrogenous hydro- 

 carbons. Entirely different chemically 

 from fats, they are nevertheless only 

 present in vivo as solutions within 

 lipoids. They generally appear yellow, 

 orange or brown in unstained frozen 

 sections mounted in syrup of levulose. 

 Lison (p. 244) indicates that tissues con- 

 taining these pigments can sometimes 

 be embedded in paraffin, because they 

 are only slowly soluble in cold alcohol. 

 They are however more quickly soluble 

 in chloroform, acetone petroleum ether 

 and toluol. According to Lison (p. 245) 

 they are always easily identifiable bj'^ 

 the fact that when treated with concen- 

 trated sulphuric acid they turn intense 

 blue before being destroyed. Treated 

 with solution of iodine-iodide (say 

 Gram's, Lugol's) they give a black green 

 or brown color. When treated with 



solution of chromic acid they lose their 

 color more or less quickly. See Lipids, 

 tabular analysis, also Carotin. 



Carr-Price Reaction for vitamin A. When 

 frozen sections of liver are plunged 

 directly into a solution of antimony 

 trichloride in chloroform and immedi- 

 ately examined therein mitochondria 

 take bright blue color which fades within 

 30 min. (Bourne, G., Austral. J. Exp. 

 Biol. & Med. Sci., 1935, 13, 238-249). 

 Antimony trichloride is said not to be 

 specific for vitamin A since it also gives 

 blue color with carotinoid pigments 

 (Bourne, p. 106). 



Cartilage. This is one of the most awkward 

 tissues of the body to examine in the 

 living state because of the mechanical 

 difficulties involved in separating its 

 component parts sufficiently thinly for 

 examination at high magnification in 

 approximately isotonic media. But the 

 differentiation of cartilage in tissue 

 cultures has been studied to advantage 

 (Fell, H. B., Arch. f. exper. Zellf., 

 1929, 7, 390-412) and an account of the 

 direct investigation of living cartilage 

 in Sandison transparent cliambers in- 

 serted in the ears of rabbits (Clark, E. 

 R., and E. L., Am. J. Anat., 1942, 70, 

 167-200) sounds very promising. The 

 varieties of cartilage (hyaline, articular, 

 elastic and fibrous) depend upon the 

 quantitative and qualitative differences 

 in the three chief components — cells, 

 fibers and ground substance. 



When the cartilage is fixed to bone, 

 which is also to appear in the sections, 

 it is obviously necessary to employ 

 decalcification, see Bone. Otherwise 

 cut thin slices, 2-4 mm. tiiick, and fix by 

 immersion. Fixation by perfusion is 

 not a great help because cartilage is 

 practically avascular. The choice of 

 fixatives and stains will depend upon 

 what it is desired to demonstrate. For 

 routine purposes Zenker's Fluid is 

 satisfactory followed by coloration of 

 paraffin sections with Hematoxylin and 

 Eosin or Mallory's Connective Tissue 

 stain. But many prefer Celloidin sec- 

 tions. Resorcin Fuchsin is recom- 

 mended for the elastic fibers of the 

 matrix. Since the fibers are somewhat 

 obscured by the ground substance in 

 hyaline cartilage dark field and polarized 

 light may be useful as employed by 

 Lubosch, W., Zeit. f. mikr. Anat., 

 Forsch., 1927, 11, 67-171. A paper by 

 Dawson, A. B., and Spark, C, Am. J. 

 Anat., 1928, 42, 109-137 also contains 

 useful information. If it is desired to 

 show the Golgi apparatus in the cells 

 follow the tecnnique used by Fell, H. 

 B., J. Morph., 1925, 40, 417-459. See 

 Chondriotin Sulphuric Acid and Phos- 

 phatase as components of cartilage. 



