120 THE MECHANISM OF LIFE 



precipitated membranes are hydrated substances, and some of 

 them, like the ferroeyanide of copper and the tannate of 

 gelatine are, when first formed, entirely comparable to liquid 

 membranes in all their properties. 



"Graham had already obtained colourless jellies by the 

 interaction of concentrated solutions of ferroeyanide of potas- 

 sium and sulphate of copper. Biitschli also has recently 

 described the microscopic appearance of precipitated mem- 

 branes produced by ferroeyanide of potassium and acetate or 

 chloride of iron. 



" Like Linke and Gustav Rose, Famintzin has obtained 

 spheroidal precipitates by the reciprocal action of concentrated 

 solutions of chloride of calcium and carbonate of potassium. 

 These grow rapidly and suddenly, with concentric layers 

 showing a spherical or flattened nucleus. He also obtained 

 forms resembling sphero-crystals and starch grains. 



" Halting. Vogelsang, Hansen, Biitschli, and others have 

 studied the structures which are formed by the reciprocal 

 action of chloride of calcium and the alkaline carbonates. 

 Vogelsang has found small calcareous bodies in the amorphous 

 and globular precipitate formed by chloride of calcium and 

 carbonate of ammonium. He describes spheres attached to one 

 another, vesicles, and muriform structures. The number of 

 these spheroids is increased by the addition of gelatine. 

 Hansen has also studied Ilarting's method for the formation 

 of sphero-crystals by the action of the alkaline carbonates 

 and phosphates on the salts of calcium in presence of albumen 

 and gelatine. He considers that the latter retard the crystal- 

 lization and assist the formation of the sphero-crystals. 



" I shall show later on that gelatine and albumen essentially 

 modify the precipitate and do not merely act as catalytic 

 substances. The researches of Famitzin, repeated and extended 

 by Biitschli, shou that sphero-crystals are produced by the 

 reaction of chloride of calcium on carbonate of potassium 

 without the presence of gelatine or albumen. Biitschli studied 

 the spheroids of carbonate of lime by means of polarized light, 

 and found that the layers were alternately positively and 

 negatively polarized." 



