LABORATORY STUDIES AND DEMONSTRATIONS. 223 



Collodion and Clove-oil.-Used for fixing sections to the slide 

 in order to prevent the displacement of delicate or isolated parts 

 in balsam-mounting. Mix one part of ether- collodion and three 

 parts of oil of cloves. In mounting, varnish a slide with the 

 mixture by means of a camel's-hair brush, lay on the sections 

 arid place the slide for a few minutes on the water-bath (i.e., 

 until the clove-oil evaporates). Transfer the slide to a wide- 

 mouthed bottle of turpentine (to dissolve the paraffin), remove it 

 and drain off the turpentine, place a drop of Canada balsam on 

 the middle of a cover-glass, and invert it over the object. 



Dahlia. Dissolve in water. 



^ Eosin. Dissolve in water until a bright-red solution is ob- 

 tained. It should be diluted when used. 



Glycerine, dilute. Two parts glycerine, one part distilled 

 water. 



Htematoxylin (Delafield's). Add 4 c.c. of saturated alcoholic 

 solution of hsematoxylin to 150 c.c. of strong aqueous solution of 

 ammonia-alum; let the mixture stand a week or more in the 

 light, filter, and add 25 c.c. of glycerine and 25 c.c. of methyl 

 alcohol. The fluid improves greatly after standing some weeks 

 or months. 



Haematoxylin (Kleinenberg's). To a saturated solution of cal- 

 cium chloride in 70$ alcohol add an excess of pure alum ; filter 

 after 24 hours and add 8 volumes of 70$ alcohol, filtering again 

 if necessary. Add a saturated alcoholic solution of hsematoxylin 

 until the liquid becomes purple-blue. The longer the liquid 

 stands before using, the better. It should be diluted for use 

 with the alum-calcium-chloride solution in 70$ alcohol. 



Hermann's Fluid. See Lee's Vade Mecum. 



Iodine Solution. Dissolve potassium iodide in a small quantity 

 of water, add metallic iodine until the mixture assumes a dark- 

 brown color, and then dilute to a dark-sherry color. The solu- 

 tion should be kept from the light. 



Magenta (Aniline Red). Dissolve in water. 



Methyl Green. Used in aqueous or alcoholic solution or 

 with acetic acid. 



Normal Fluid (Normal Salt Solution). Dissolve 7.50 grams of 

 sodium chloride in 1 litre of distilled water. 



Paraffin. " Hard " and "soft" paraffins, i.e., those of high 



