308 Scientific Intelligence. [Oct. 



the smell, and something of the taste, of cheese ; but being 

 changed into cheese by the progress of fermentation is the cha- 

 racteristic property of gluten. Hence it is obvious that yeast, 

 since it undergoes that change in a degree sufficiently sensible 

 to the most careless observer, must contain a quantity of gluten. 



III. Colouring Matter of the Cancer Astacus. 



It is well known that when these animals are boiled, they 

 assume a red colour. M. Lassaigne has made some experiments 

 to ascertain the cause of this developement of red. He found 

 that crabs' heads separated Avith care from the fleshy part, when 

 plunged into absolute alcohol of the temperature of b'O", speedily 

 acquire a scarlet colour, which they gradually communicate to 

 the alcohol. He steeped them in repeated doses of alcohol till 

 they ceased to communicate any colour to this liquid. The 

 crabs' heads thus treated were deprived of the property of 

 becoming red wlien boiled in water. The different alcoholic 

 solutions had a fine red colour. They were put into a capsule, 

 and allowed to evaporate spontaneously. There remained a red 

 matter which had a greasy appearance. 



This matter is destitute of taste and smell. It is insoluble in 

 water, whether hot or cold, but it dissolves in sulphuric ether, 

 and in strong alcohol, without the assistance of heat. The solu- 

 tion has a scarlet colom', and is not rendered muddy by the 

 addition of water. This shows that it is not of a fatty nature. 

 Neither potash, soda, nor ammonia, alter its colour. Even the 

 mineral acids, when diluted with water, have no action on it ; 

 but when concentrated, they destroy it by changing it into a 

 dirty yellow. Neither salts of lead, tin, iron, or copper, preci- 

 pitate this colouring matter from its alcoholic solution diluted 

 with water. M. Lassaigne informs us that this colouring mat- 

 ter is lodged in a membrane, which adheres strongly to the head 

 in young crabs, but which may be easily separated m those which 

 have attained a considerable size. This membrane is very fine, 

 and when seen by reflected light has a violet colour ; but is pur- 

 ple by transmitted light. — (Jour, de Pharmacie, vi. 174.) 



IV. Crystallization of Balsam of Copaiva. 



M. Pelletier, having broken a bottle of balsam of copaiva 

 which had been in his house for 30 years, found at the bottom 

 of the vessel a transparent plate of resin, from which proceeded 

 hexagonal plates, some of which exhibited distinctly the form of 

 six-sided prisms terminated by a face perpendicular to the axis 

 of the prism. These crystals possessed the property of polaris- 

 ing hght. — (Ibid. p. 315.) 



V. Meteoric Stone. 

 On Oct. 13, 1820, a meteoric stone fell near Kostritz, in Rus- 



