M. Mohl on the Growth of Cell-Membrane. 261 



seemed the most probable. Although I shot many in order to 

 procure a female, I only succeeded in getting the one above-no- 

 ticed, which however I cannot with certainty pronounce to be 

 one. It was shot down from a half-finished nest at more than 

 twenty yards high. Two or three nests are often attached to the 

 same leaf, and twenty or thirty in the same palm. In the be- 

 ginning of May the newly-hatched young were obtained from a 

 nest, and three quite white eggs from another, although many 

 nests were scarcely half- built. 



The notes near the nests were like the warbling and call-notes 

 of the linnet. No song was heard. In the stomach only rice- 

 grains were found, which they were seen to pluck while hopping 

 about the cottages, like sparrows with us. The Bengalese name 

 is Bawee (the w sounded as in English). 

 [To be continued.] 



XXVIII.— On the Growth of Cell-Membrane. 

 By Hugo v. Mohl*. 



[Continued from p. 155.] 



When we compare the conclusions necessarily resulting from 

 these calculations with Harting's theory, we see that they are 

 decidedly opposed to it. We have good grounds for the assump- 

 tion that the mean number, derived from the measurement of 

 ten rows of cells, indicates with tolerable accuracy the course of 

 the normal development of the wood-cells of Hoya carnosa, since 

 the mean numbers already derived from the measurement of 

 five rows of cells differ but very slightly from those above men- 

 tioned. If we assume this, it follows that the nearer the inter- 

 mediate (mittlere) wood-cell (if I may so express myself) of this 

 plant approaches the margin of the wood in consequence of the 

 progressive conversion of the inner cambium-cells into wood- 

 cells, the more it enlarges in the radial direction, so that its dia- 

 meter is T ^2 of a millimetre when it lies in the second row of 

 cambium-cells (counted from the wood), and when it has advanced 

 to the inner row, bordering the wood, the diameter is increased 

 to g l Q of a millimetre. According to Harting's view, the cavity of 

 the cell will continue of this sizef, since in his opinion the con- 



* From the ' Botanische Zeitung,' May 29th and June 5th, 1816. Trans- 

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



f I here take the diameter of the cavity of the cell as equalling the dia- 

 meter of the whole cell, which is not altogether right, but deviates little from 

 the truth, since the cambium-cells of Hoya carnosa have very thin walls, and 

 as these walls are double, only half this thickness should be reckoned. This 

 is so small a size and one so difficult to give accurately that 1 thought it might 

 be disregarded; in a measurement which however cannot claim strict ac- 



