[ 247 ] 



L. A B-e-port of the Progress of Phytochemistry in the year 

 1835, in reference to the Physiology of Plants. By J. Cl. 

 Marquart.* 



nPHE experiments on starch which were mentioned by 

 "^ M. Meyen in his Annual Report on Physiological Botany 

 for 1834' tj have been continued in various ways. According 

 to the experiments of MM. Payen and Persoz:]:, starch con- 

 sists of 995 p. m. interior substance, which they call amidone, 

 and 3 p. m. teguments. The other two thousandth parts they 

 reckon as carbonate and phosphate of lime with silica. They 

 found also in the starch of native plants a disagreeably smell- 

 ing oil, soluble in alcohol, which was not contained in exotic 

 starch. Amidone is insoluble in water as long as it remains 

 unchanged ; it only swells in it, and then passes through se- 

 veral filters. 



The apparent solubility of amidone in water of 65 — 70° 

 [Cent.] is therefore properly only a suspension of it, effected by 

 means of the greatest divisibility possible. The known qua- 

 lities of starch solutions belong to this amidone; neither dia- 

 stase nor iodine, &c., act on the tegument, whose nature is not 

 further characterized. The authors also critically illustrate 

 the results of M. Guerin's experiments (Annual Report for last 

 year, p. 145), and consider his amidine to be their amidone in 

 a state of great division, with a portion decomposed by his 

 method of experimenting; on the contrary, they regard his 

 amidin soluble to be amidone swelled by water. M. Guerin 

 soon answers these objections §, and maintains, supported by 

 experiments, that the amidone of MM. Payen and Persoz 

 consists of a soluble and an insoluble part. The dextrine^ 

 which MM. Payen and Persoz formerly considered to be the 

 contents of the starch granules, is a product of the action of 

 acids on the amidone and is a mixture of sugar, gum, and ami- 

 done. 



M. Guerin Varry studied || more attentively the action of 

 diastase on the starch granules, and found the doubt, already 

 expressed by M. Meyen in the Report for last year (p. 151) 

 to be true, that diastase is capable of rending the tegument of 

 the starch granule. The starch, which had been left un- 

 changed by hot water, remained, according to M. Guerin, 

 quite unchanged by diastase even by -f 20 — 26° Cent.; the 

 amidone, on the contrary, is changed by it partly into sugar 



♦ From Wicgmann's Arcluv fiir Naturfj;eschichte, vol. ii. part iv. p. 131. 



f See Wiej^inann's Arrhiv, vol.i. p. 143. 



t Annates de Chimic ct (k Plit/nque^ Aout 1834, p. 337—371. 



I Ibid., Sept. 1834, p. 108, 109. |1 Ibid. Sept. 1835, p. 32—78. 



