EXAMINATION AND PRESERVATION MEDIA. 271 



393. Aqueous Humour, Simple White of Egg. Require no 

 preparation beyond filtering. They may be iodised if desired. 



394. Artificial Iodised Serum (FREY, Das Mikro*linp } 6 Aufl., 



1877, p. 75). 



Distilled water . . . . 270 grms. 



White of egg .... 30 ,, 



Sodium chloride . . . . 2 '5 ,, 



Mix, filter, and add tincture of iodine. 



395. KRONECKER'S Artificial Serum (from VOGT et YUNG, 

 Trtiiti' d'Anat. comp. prat., p. 473). 



Common salt ..... 6 grms. 



Caustic soda . . . . . 0'06 grm. 



Distilled water ... 1 000 grms. 



BOHM und OPPEL (Taacheribuch, 3 Aufl., p. 19) take car- 

 bonate of soda instead of caustic soda. 



396. MIGULA'S G-lycerizecl Blood-serum (see the paper in Zeit.f. iwiss. 

 Mik., vii, 2, 1890, p. 172 ; also Journ. Roy. Mic. Soc., 1890, p. 804). 



397. 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, or 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. 



398. Chloride of Calcium (HARTIXG, Das Mikroskop, 2 Aufl., p. 297). 

 The aqueous solution, either saturated or diluted with 4 to 8 parts of 

 water, has a low refractive index and does not dry up. 



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

 p. 180). A nearly saturated solution in water. The index of refraction is 

 lower than that of glycerin. 



