THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY 



No. 118. SEPTEMBER 1846. 





XVI. — On the Growth of Cell- Membrane. By Hugo v. Mohl*. 



Since my doctrine, that cell-membrane increases in thickness 

 by the deposition of successive layers of membrane deposited 

 internally, has recently been contradicted on various sides, and, 

 in opposition to it, the theory has been propounded, that the 

 innermost cell-layer is the oldest and the most external the 

 youngest, it is only natural that I should accept the challenge 

 and enter the lists in defence of my views. 



The first attack proceeded from Prof. Hartig of Brunswick : 

 I endeavoured to set aside his objections to my view two years 

 ago in the ' Botanische Zeitung'f, without success so far as that 

 author was concerned, as since that time a second treatise of his 

 has appeared (Das Leben der Pflanzenzelle, 1844), which conr 

 tains an answer to my objections and a more extended exposition 

 of his theory. In reference to this second treatise however I 

 must stand aloof, since my own observations agree so little with 

 the researches there brought forward, that they afford me no 

 point on which I can bring forward either opposition or confir- 

 mation ; in the following pages therefore I can take no notice of 

 it. Otherwise it is connected with the observations on which 

 the Utrecht professors, Harting J, and Mulder § rest their objec- 

 tions to my theory. As to the matters of fact in these researches 

 I agree in many respects with my honourable adversaries, and 

 there are I believe but few points which they have not taken into 

 consideration, these however I must bring forward against the 

 conclusions they have drawn. 



According to my views, the primary membrane of the young 

 cell is not perforated with orifices, and certainly no definite 

 structure is visible in it||. On the other hand, Harting and 



* From the ' Botanische Zeitung,' May 15th— 22nd, 1846. Translated by 

 Arthur Henfrey, F.L.S. &c. 



t Jahrg. ii. 273. Scientific Memoirs, vol. iv. p. 91. 



J Mikrochemische onderzookingen, &c, vide Bot. Zeit. Jahrg. iv. p. 64. 



§ Versuch einer physiologischen Chemie. 



|| Vide my essay on the Structure of Vegetable Cell- Membrane in my 

 Vermischte Schriften, p. 314. 



Ann. $ Mag. N. Hist. Vol. xviii. M 



