CALCIUM CHLORIDE. 235 



364. Aqueous Humour, Fruit Juice, Simple White of Egg. 

 Require no preparation beyond filtering. They may be iodised 

 if desired. 



365. Syrup. An excellent medium for examining many 

 structures in the fresh state. To preserve it from mould, 

 chloral hydrate may conveniently be dissolved in it (1 to 5- 

 per cent.). I have used as much as 7 per cent., and found no 

 disadvantage. 



Carbolised Syrup. Carbolic acid may be employed instead 

 of chloral ; 1 per cent, is sufficient. 



Either of these syrups may be used as a mounting medium, 

 but they are not to be recommended for that purpose, as there 

 is always risk of the sugar crystallising out. 



A good strength for syrup is equal parts of loaf sugar and 

 water. Dissolve by boiling. 



366. Saliva. Saliva has been recommended with the idea of its being 

 innocuous to delicate structures ; it is of course a macerating agent (see 

 MACEBATING AGENTS, Artificial Saliva). 



367. Carbolic Acid. 1 per cent, in water. Is a mounting medium. 



368. Kreasote. 5 per cent, in water. 



369. Thwaites' Kreasote Fluid (see BEALE, How to Work, &c., p. 55). 



370. Beale's Naphtha and Kreasote (ibid., p. 56). 



371. Quekett's Wood-naphtha Fluid (ibid.). 



372. Alum Sea-water. A saturated solution of alum in sea- water is 

 useful for the examination and preservation of the tissues of many marine 

 organisms (Medusae, Siphonophora, Ctenophora, Pelagic Tunicata). The 

 animals may be killed in the fluid, which is a fair fixing agent. 



373. Acetate of Alumina (GANNAL'S SOLUTION, BEALE, ibid.). 



Acetate of alumina ..... 1 part. 

 Water 10 parts. 



374. Acetate of Potash (MAX SCHULTZE, Arch. mik. Anat., vii, 1872, 

 p. 180). A nearly saturated solution in water. It is used by letting a drop 

 run in under the cover-glass to the object, which is in water. After twenty- 

 four hours the mount may be closed. The index of refraction is lower than 

 that of glycerin. 



This medium has been frequently recommended as having the property of 

 preventing the blackening of objects that have been 'treated with osmium ; 

 but it seems extremely doubtful whether this is really the case. 



375. Calcium Chloride (Micro. Diet., art. " Calcium, chloride "). 

 Either about 1 part of the salt to 2 of water, or a saturated solution may be 

 used. A lump of camphor should be added to the solution to preserve it. 



