242 MACERATION AND DIGESTION. 



For vibratile epithelium, Ranvier finds the mixture inferior 

 to one third alcohol. 



501. Chloral Hydrate, In not too strong solution, from 2 to 

 5 per cent., for instance, chloral hydrate is a mild macerating 

 agent that admirably preserves delicate elements. LAVDOWSKY 

 (Arch. f. mik. Anat., 1876, p. 359) recommends it greatly 

 for salivary glands. HICKSON (Quart. Journ. Mic. Sci., 1885, 

 p. 244) recommends it for the study of the retina of 

 Arthropods. 



502. Caustic Potash, Caustic Soda. These solutions must be 

 employed strong , 35 to 50 per cent. (Moleschott) : so employed 

 they do not greatly alter the forms of cells, whilst weak solu- 

 tions destroy all the elements. (Weak solutions may, how- 

 ever, be employed for dissociating the cells of epidermis, 

 hairs, and nails.) The strong solutions may be employed by 

 simply treating the tissues with them on the slide. It should 

 be remembered that preparations obtained by means of these 

 alkalies cannot be permanently preserved. 



503. Sulpho-cyanides of Ammonium and Potassium (STIRLING, 

 Journ. Anat. and Phys., xvii, 1883, p. 208). Ten per cent, 

 solution of either of these salts is an admirable dissociating 

 medium for epithelium. Macerate small pieces for twenty- 

 four to forty-eight hours, stain with f uchsin, eosin, or picro- 

 carmine. 



If a crystalline be macerated as above its fibres become 

 beaded or moniliform. 



504. Saliva, Artificial (for embryology of nerve and muscle) 

 (CALBERLA'S formulae, Arch.f. mik. Anat., xvi, 1879, p. 471, 

 et seq). After having made trial of various different mace- 

 rating agents, with the object of obtaining isolation of the 

 developing muscle and nerve of embryos of Amphibia and 

 Ophidia, Calberla found that the best results were obtained 

 by means of Czerny's mixture of saliva and solutio Million. 

 This led him to imagine an artificial saliva, which on trial 

 gave results as good as those obtained by natural saliva, o v 

 even better. 



Second formula (the first formula is suppressed, as being 

 more complicated, and not giving better results) : 



