CHAPTER XIX. 219 



d'Anat. Comp. Prat., p. 473) consists of common salt 6 parts, caustic 

 soda 0-06, distilled water 1000. 



BOHM und OPPEL (Taschenbuch, 3 AufL, p. 19) take carbonate of 

 soda instead of caustic soda. 



403. PICTET'S Liquid (Mitth. Zool. Stat. Neapel, x, 1891, p. 89). 

 5 to 10 per cent, solution of chloride of manganese. These propor- 

 tions are for marine animals, and for terrestrial animals will generally 

 be found much too high. For these from 1 to 3 per cent, will be 

 nearer the mark. I find this liquid excellent. 



404. Aqueous Humour, Simple White of Egg. Kequire no pre- 

 paration beyond filtering. They may be iodised if desired (see 

 next ), or mixed with salt solution. 



405. Iodised Serum. MAX SCHULTZE (Vir chow's Archiv., xxx, 

 1864, p. 263). I take the following from KANVIER (Traite, p. 76). 



The only serum that gives really good results is the amniotic 

 liquid of mammals. Flakes of iodine are added to it, and the flask 

 frequently agitated for some days. The flask should have a wide 

 bottom, so that the serum may form only a shallow layer in it. 



Another method is as follows : Serum is mixed with a large 

 proportion of tincture of iodine ; the precipitate that forms is 

 removed by filtration, and there remains a strong solution of iodine 

 in serum. This should be kept in stock, and a little of it added 

 every two or three days to the serum that is intended for use. In 

 general for maceration purposes a serum of a pale brown colour 

 should be employed. 



406. Artificial Iodised Serum (FREY, Das Mikroskop, 6 Aufl., 

 1877, p. 75). Distilled water 270 grms., white of egg 30, sodium 

 chloride 2-5. Mix, filter, and add tincture of iodine. 



407. MIGULA'S Glycerised Blood-serum (see the paper in Zeit. /. wiss. 

 Mik., vii, 2, 1890, p. 172). 



408. Chloride of Calcium (HARTING, 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. 



409. Acetate of Potash (MAX SCHULTZE, Arch. mile. Anat., vii, 1872, 

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

 is lower than that of glycerin. 



410. Syrup. A good strength is equal parts of loaf sugar and 

 water. Dissolve by boiling. To preserve it from mould, chloral 

 hydrate may 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 

 (1 per cent.). 



