STAINS, ETC. 



1378 



EXAMINATION MEDIA 



frog with a fine capillary pipet. Blood-serum. The 

 blood is allowed to clot, and in a day or two the serum 

 is poured ott, and any red corpuscles removed from it 

 by means of a centrifugal apparatus. This fluid does 

 not keep, and must be fresh for use. Iodin is some- 

 times added, forming iodized serum. Chloral. One, 

 2. 5, and 5 per cent, aqueous solutions are recommended 

 by Munson, Brady, and Landowsky respectively. 

 Frey's Artificial Iodized Serum. To a filtered 

 mixture of white of egg 15 gm. , sodium chlorid 0.2 

 gm., distilled water 135 c.c, add 3 c.c. of tincture of 

 iodin. Filter through flannel, and add a little iodin to 

 the filtrate. Fruit-juice requires no preparation 

 beyond filtering. It may be iodized. Iodized 

 Serum. To the fresh amniotic liquid of a sheep or cow 

 add iodin crystals. Keep the solution in a stoppered 

 bottle and shake frequently. It should acquire a dark- 

 brown color. Kronecker's Artificial Serum. Sod- 

 ium chlorid 6 gm., sodium hydroxido.06 gm. , distilled 

 water 1000 c.c. Normal Salt-solution. Sodium 

 chlorid from 6 to 7.5 gm., distilled water 1000 c.c. 

 Used in the study of living structures. Physiologic 

 Salt-solution. See Normal Salt-solution. Syrup. A 

 good medium for examining fresh structures, and pre- 

 pared by dissolving equal parts of loaf-sugar in water 

 by boiling. The addition of I per cent, of carbolic 

 acid or chloral will preserve it from mold. Water. 

 Structures fixed in osmic or chromic acid, or a solution 

 of a metallic salt, may be examined in water, which 

 has the advantage of having a low index of refraction. 

 A little thymol will preserve it from mold. White 

 of Egg needs only to be filtered to prepare it for 

 use. It may be iodized. II. Glycerin and Other 

 Fluid Media. Acidulated Glycerin. Glycerin 

 50 c.c, glacial acetic acid or formic acid 1 c.c, dis- 

 tilled water 50 c.c. Used after staining in borax or 

 lithium-carmin, previous to mounting in glycerin. 

 Beale's Glycerin-jelly. Equal parts of pure glycerin 

 and gelatin, soaked, melted, and clarified. Brandt's 

 Glycerin-jelly. Melted gelatin 1 part, and glycerin 

 1.5 parts. Filter through spun glass, and add a few 

 drops of carbolic acid to the filtrate. For mounting, 

 melt a little on the slide, having previously soaked the 

 object for a short time in the medium warmed by gentle 

 heat. Calberla's Liquid. One part each of glycerin, 

 alcohol, and water. A valuable examination fluid. 

 For very delicate objects, Lee recommends the same 

 formula, with two parts of water instead of one. 

 Calcium Chlorid. A 50 per cent, or saturated solu- 

 tion is used. The addition of a little camphor will 

 preserve it. As this salt is very hygroscopic, the mount 

 need not be closed at once. Carbolic Acid. A I per 

 cent, solution is used as a mounting-medium. Car- 

 noy's Solutions. 1. A concentrated aqueous solution 

 of methyl-green containing I per cent, of acetic acid 

 and o. 1 per cent, of osmic acid, used in the study and 

 preservation of fresh tissues. It has a selective action 

 on nuclei. 2. Powdered tannin 0.5 gm., water 100 

 c.c Castor-oil. Recommended by Grenacher, on 

 account of its low refractive index, for certain delicate 

 tissues (sections of eyes of Ce/>lialo/>ods), on the sup- 

 position that it would augment visibility for the more 

 refractive elements of these tissues. Copper Acetate. 

 A solution of I gm. of copper acetate and 4 gm. of 

 mercuric chlorid in 250 c.c. of glycerin and 1 c.c. of 

 glacial acetic acid is used in preserving and mounting 

 green algx'. Creasote. As a mounting-medium, a 5 

 percent, aqueous solution is used. Deane's Glycerin- 

 jelly. Dissolve 30 gm. of gelatin in 60 gm. of 

 water, and add 120 gm. of glycerin. This must be 

 used warm. Fabre-Domergue Glucose Medium. 

 Dissolve glucose in warm water and dilute to 25 of 



the areometer (sp. gr. 1.1968). To 1000 parts of this 

 solution add 200 parts of methyl -alcohol, 100 parts of 

 glycerin, and camphor to saturation. Neutralize by the 

 addition of a little potash or soda. This medium i> 

 said to preserve, unchanged, nearly all animal pig- 

 ments. Farrant's Solution {Hamilton). Make a 

 saturated solution of arsenious acid in water by boiling, 

 let it stand twenty-four hours, and filter. Then to equal 

 quantities of water, glycerin, and arsenious acid boin 

 tion add picked gum arabic until a thick, syrupy fluid 

 is obtained. In about a week, filter slowly through 

 frequently changed filter-paper. Fol's Glycerin-jel- 

 lies. I . Melt together one volume of Beale's jelly and 

 one volume of water, and add 2 to 5 per cent, of car 

 bolic acid. 2. Gelatin 30 parts, water 70 parts, gly- 

 cerin, 100 parts, alcoholic solution of camphor 5 parts. 

 3. Gelatin 20 parts, water 150 parts, glycerin 10c 

 parts, alcoholic solution of camphor 15 parts. Gage's 

 Fluid. Mercuric chlorid o. 5 gm. , salt 4 gm. , white of 

 egg 15 c.c. , water 200 c.c. Mix thoroughly and filter. 

 Used in the study of ciliated cells and red blood-cor 

 puscles. Gannal's Solution. A preserving mediun 

 consisting of aluminum acetate I part, and water 11 

 parts. Gilson's Fluid. Mercuric chlorid 0.15 gra. 

 15 per cent, acetic acid 2 c.c, 60 per cent, alcohol 6c 

 c.c, and water and glycerin each 30 c.c. An admir 

 able medium for the study of fine cellular detail ii 

 well-fixed tissues. Glycerin. As a medium for ex 

 amination and mounting, glycerin is usually diluted will 

 water, which lowers its index of refraction, often ai 

 advantage from an optic point of view , on account 

 the increased visibility it gives to many structures. < > j 

 the other hand, undiluted glycerin has the advantag 

 of being a more efficacious preservative. Object 

 mounted in glycerin should be subjected to a prolonge 

 preliminary soaking in glycerin of gradually ini 

 strength ; if done on the slide, and treated with fres ; 

 glycerin daily, the edges of the cover-glass should I 

 luted to make the preparation air-tight, glycerin bein 

 so hygroscopic as to rapidly diminish in strength whe 

 exposed to air. To facilitate the removal of the cove 

 glass, warm the slide gently ; this treatment will al; 

 counteract the shrinking action of glycerin on delica 

 tissue-elements and restore them to their normal coi 

 tour and dimensions. Glycerin, being a solvent of cr ' 

 cium carbonate, is not a suitable medium for the pr 1 

 paration of calcareous structures. By dissolving 

 glycerin cadmium chlorid, chloral, and certain oth 

 substances, its index of refraction may be raised 

 about that of crown-glass, which greatly augments 

 clearing action, and allows the full aperture of hom 

 geneous objectives to be brought to bear on the objci 

 A saturated solution of zinc sulphocarbolate in glycei 

 will raise its index of refraction from 1 .46 to 1 

 is prepared by taking equal parts by weight of Pried 

 glycerin and zinc sulphocarbolate, and boiling for 

 hour or more. Filter while hot. Glycerin and A! 

 cohol. Useful for bringing delicate objects gradua 

 from weak into pure glycerin. Glycerin 

 alcohol 1 part, water 2 parts. Glycerin-jelly. So 

 in 150 c.c. of distilled water, 25 gms. of gelatin 

 two hours, and add 3 c.c of carbolic arid and I 

 c.c. of glycerin ; heat for fifteen minutes and nl 

 through spun glass. Wrap the cork of the bottle 

 which the jelly is preserved in linen dipped in dilij 

 carbolic acid. For use, melt it in hot water, pl*e< 

 drop on the section, upon which gently press a Coi 

 glass. Glycerin and Gum. Useful when th 

 ous acid of Farrant's medium is objectionable 

 chloroform -water (I : 200) 200 c.c. gum acacia I 

 gin., and glycerin IOOC.c. Dissolve the gum in I 

 chloroform- water, with frequent stirring and wiili" 



