264 Observations upon Siliceous Deposits, fyc. 



gelatinous state), as fluids frequently do, to the kidneys by some 

 less circuitous route than the circulation, it is possible to con- 

 ceive ; but that it could pass in a crystallized state, either by 

 this shorter route, or through the more circuitous one of the 

 circulation, I think will not readily be admitted. There is no 

 other way, then, of accounting for the appearance of this sin- 

 gular deposit, but its secretion by the kidney, and its separa- 

 tion, as other morbid concretions. Nor is there more difficulty 

 in conceiving the kidney capable, under certain circumstances, 

 of such an elimination, than an operation of which there can 

 be no question the formation of the CYSTIC OXIDE. 



NOTES UPON VEGETABLE TISSUE. By JOHN LINDLEY, 

 Esq., F.R.S., &c. 



No. 1. Cellular Tissue. 



T> OTANISTS generally recognize three principal elementary 

 forms of tissue, of which, under a variety of modifications, 

 all the parts of plants are constituted ; these forms are the cel- 

 lular, the fibrous, and the vascular. As far as regards tissue, in 

 a state of perfect organization, the limits of these divisions are 

 sufficiently exact, and the latter may be understood as elemen- 

 tary forms ; but, if we consider tissue with reference to its own 

 constituent parts, we shall find that these three principal forms 

 are constructed of something still more elementary: viz., mem- 

 brane and fibre ; and that, under the head of cellular tissue, are 

 really comprehended certain modifications, composed of no- 

 thing but the latter elementary matter. 



Cellular tissue is well known to be the basis of vegetation, 

 to be that form which is indispensable to the existence of a 

 vegetable being, and, therefore, to be in all cases present; 

 while the two other forms are present or absent in plants ac- 

 cording to their species. In its most common state, it consists 

 of numerous minute, imperforate, transparent vesicles, pressing 

 the one against the other, and by this pressure acquiring various 

 figures, such as the dodecaedral, the prismatic, the columnar, 

 the cubical, &c. ; its sides are destitute of all markings, except 



