354 Mr Carry, On some points in the structure and [Ap. 30, 



palisade tissue generally, and argues that since one and the same 

 leaf contains palisade cells both with and without pseudo- 

 ingrowths the physiological functions performed by the two 

 sets of cells is the same. He believes that the cells in which 

 pseudo-ingrowths occur irregularly are simpler than those in 

 which they have a tolerably definite relation to the periphery of 

 the leaf, and simpler also than the ordinary palisade cells which 

 are destitute of any such infoldings ! Since a fold projecting 

 into the lumen of a cell must of necessity increase the inner 

 surface of the cell-wall, and this is correlated with the fact that 

 the chlorophyll corpuscles always lie in close contiguity with 

 the walls of the cell, he argues that the function of such an in- 

 folding must be to increase the efficiency of the cell as an assimi- 

 lating organ by affording space for more chlorophyll corpuscles 

 within a given area. As already mentioned, the protoplasm 

 (primordial utricle) close to the pseudo-infoldings is always beset 

 with chlorophyll corpuscles, so that this argument is fairly borne 

 out by the facts. He however goes still further. Excluding any 

 direct causal relation of the infoldings with illumination by light 

 on account of their irregular direction, he considers any idea 

 that they might serve to afford increased facility for the trans- 

 mission of air into the interior of the leaf refuted by the fact that 

 in Trollius europceus, Bambusa Simonii and, according to his 

 researches, frequently in Pinus no air-space exists between the 

 limbs of the closely apposed folds, which ought of necessity to be 

 invariably present on this view of their function. Such air-spaces 

 however he admits do exist in the infoldings of Sambucas nigra, 

 Pceonia tenuifolia, and Anemone silvestris, and there they are 

 sometimes moderately broad. He concludes that the physiological 

 principle of increase of surface conditions the presence of these 

 pseudo-infoldings, which he evidently considers to be a definitely 

 designed, and not as they are a comparatively accidental feature, 

 and that their number and size are determined also by the same 

 cause ; although at the same time he considers his explanation 

 unavailable for those in the leaves of Coniferas. He would 

 also explain the size, number, and occurrence of the actual 

 radial longitudinal partition-walls between the palisade cells by 

 the same method and compares them simply to completed in- 

 foldings and the pseudo-ingrowths to incomplete partition walls ! 

 Conclusions such as these based upon an entire misconception 

 of the real mode of origin and development of the apparent in- 

 growths and of their morphological nature are of neci'ssil\ 

 erroneous. From the account I have given it will be at once 

 evident that no correlation as to their mode of formation such 

 as Haberlandt would institute between the radial longitudinal 

 partition-walls and the pseudo-infoldings is at all possible. The 



