STRUCTURE.] STARCH ITS PHYSICAL QUALITIES. 113 



they produce little sprouts like themselves from their sides. 

 Turpin states that, if examined after fermentation has been 

 going on for some hours, they will be found to have each 

 formed several new granules exactly like the mother-granules; 

 and he not only considers this to be the cause of the curious 

 phenomena observable in fermentation, but regards the 

 granules as seeds and the result of their growth as a plant, 

 which he calls To-rula cerevisite. He adds, that in the inside 

 of each of the new granules formed during fermentation, he 

 finds a number of still smaller granules. I have not repeated 

 the observations of this writer further than to ascertain that 

 the granules in fermentation do sprout ; and that they have 

 at that time lost all their starch, for iodine produces no 

 sensible effect upon their colour ; a circumstance to which 

 he has not adverted. 



The true nature of starch is a modern discovery, and has 

 been determined with great precision by the successive ob- 

 servations of Raspail, Fritzsche, Payen, Mohl, Schleiden, and 

 others. The following admirable explanation is abridged from 

 the latter author's Grundziige, 2nd edition, 1845 : 



Starch, when dry, is tolerably hard, and falls to powder 

 when rubbed between the fingers ; when moist, it is rather 

 gelatinous ; when dried from solution it at first forms a trem- 

 bling jelly, and afterwards becomes vitreous, brittle, and as 

 clear as water (even in Lichens) ; when perfectly clean and 

 fresh from the plant, starch gradually dissolves in water (or 

 only disperses? for the so-called solution cannot pass through 

 a cellular membrane) \ in the plant it is usually protected 

 from solution by an incrusting wax, albumen,* mucus, or 

 any such substance outside. Starch is easily (partially) so- 

 luble in boiling water, acids, and alkalies ; insoluble in alcohol, 

 ether, volatile or fat oils ; it is stained blue by iodine, even 

 in dilute solutions, (and the iodide of starch is not more 

 soluble in water than ordinary starch, but it is insoluble in 

 acids.) It appears to be changed through intermediate 

 matter, as for instance, Lichen starch, into Amyloid ; through 

 the material discovered by Henry in the mace, into mem- 



* Used in the sense of Chemists, not of Vegetable Physiologists. 

 VOL. I. 1 



