Mr. Croft on some Salts of Cadmium. 355 



I stated, when speaking of the spontaneous decomposition 

 of wheaten dough, that an acid state preceded that in which 

 it became an alcoholic ferment ; and if in this condition it be 

 mixed with a dilute solution of common sugar, and the whole 

 kept warm for several days, it furnishes a sour liquid which is 

 rich in lactic acid, and from which white crystallized lactate 

 of zinc is easily prepared. There is a tendency in the liquid 

 to run into the alcoholic fermentation, and to produce vinegar 

 by a subsequent change, but still the quantity of lactic acid so 

 formed is very considerable. 



Common wheat-gluten then in its mode of decomposition 

 strikingly resembles diastase ; like that substance it runs in 

 succession through two different dynamic conditions ; it is 

 successively a lactic acid and an alcohol ferment; is it too 

 much to expect that it might by proper means be detected in 

 a third condition, namely, as a " sugar ferment," like diastase 

 itself in the state in which it exists in malt ? Is it not possible 

 that diastase, as a definite proximate principle, has no more 

 existence than yeast ; that its powers are purely dynamic, and 

 that it is, in short, nothing more than the gluten of the seed 

 in one of its earliest stages of decomposition? This is an in- 

 teresting inquiry, but its prosecution will be somewhat difficult 

 from the rapidity with which these changes succeed each other ; 

 it must be remembered that no one has yet succeeded in get- 

 ting diastase in a state fit for analysis. 



LXV. On some Salts of Cadmium. By Henry Croft, Esq.* 



/"^ HLORIDE of cadmium is exceedingly soluble in water and 

 ^- / cannot be obtained in good crystals. If it be treated with 

 a solution of ammonia, it is not at first dissolved ; but on heat- 

 ing, the white powder which is at first formed, disappears, 

 and on cooling a granular crystalline powder falls out of the 

 solution. It is a compound of the chloride with ammonia. By 

 heating, it loses 16'63 per cent of ammonia ; according to the 

 formula CdCl + H 3 N it would lose 15*12; the excess ob- 

 tained is owing to a portion of the chloride being decomposed 

 when sal-ammonia is evolved. The proof of this is that the 

 heated salt is not perfectly soluble in water. 



If dry ammonia be passed over pulverised anhydrous chlo- 

 ride of cadmium, the powder increases greatly in bulk under 

 evolution of heat. At first there is but little action, and the 

 stream of ammonia must be passed over the salt for some time 

 before violent absorption takes place. 1*276 gr. absorbed 



* Communicated by the Chemical Society, having been read May 1 7, 1842. 



