142 Dr. Meyen's Researches in Physiological Botany. 



this is very improbable ; for it was shown at length in the 

 former Report, that it is exactly these secondary layers, which 

 by boiling with an alkali, &c, are converted into a starch-like 

 substance ; besides, the microscope should have been used be- 

 fore those analyses were made, but such observations are not 

 mentioned. 



In the meeting of the Parisian Academy on the 14th of Ja- 

 nuary, M. Payen read a paper, entitled " Memoire sur les ap- 

 plications theoretiques et pratiques des proprietes du tissu 

 elementaire des Vegetaux*," the contents of which are of con- 

 siderable interest, but would here lead us too far into the pro- 

 vince of Chemistry. 



On the 4th of February, 1839, new researches were made 

 public by M. Payen; he gave the composition of the incrust- 

 ing matter of wood as C 3b H 24 O 10 , while the formula for the 

 primitive cellular membrane is C 24 H 20 O 10 or C 24 H 18 O 

 + H 2 O. In the sitting of the Academy of the 30th of July, 

 a new treatise by M. Payen was read, "On the tissue of 

 Plants and on the incrusting substance of Woodf/' an extract 

 from which has been published by the author. M. Payen re- 

 marks, that he had already made known to the Academy his 

 researches, according to which all young parts of plants con- 

 tain a considerable portion of substances containing nitrogen ; 

 that moreover the peculiar substance of the membranes in 

 different plants has always the same composition ; and that in 

 those parts which are grown woody by age, there are con- 

 tained two chemically different substances, viz. the primitive 

 membrane and the hard incrustation. 



" Many tissues," observes M. Payen, a acquire a high degree 

 of hardness without possessing large quantities of incrusting 

 matter." (In the same manner we may bring forward cases 

 where many cells with thickened sides have no hardness, and 

 it is evident from this that the hardness of the vegetable sub- 

 stance does not depend solely on the thickening of the walls 

 of the cells, but on the chemical change in the layers of cel- 

 lular membrane, M.) The latest analyses and microscopical 

 observations of M. Payen have led him to conclude that wood 

 consists of not less than four different substances, viz. the pri- 

 mitive cellular membrane, and the sclerogene, which again is 

 said to consist of three peculiar matters ; the one insoluble in 

 water, alcohol, and aether, the other soluble in alcohol, and 

 the third in all three solvents. The ultimate composition of 

 these four substances in the above order is as follows : — 



* Comptes Rendus de 14 Janv. 1839, p. 59. 

 t Ibid. 20 Juill. 1839, p. 149. 



