OF VEGETABLE TISSUES. 201 



movement or force is functional ; yet all which the microscope reveals is so closely allied to 

 the physical, that some are constrained to regard the incipient stage of a cell as formed by 

 physical forces. In tracing backwards the changes incident to the formation of a cell, we may 

 probably regard all the visible changes as functional. A granule preceding a cell, as one of 

 its stages, performs no doubt, a function, without which no cell would be completed, but the 

 granule performs none of the functions of an individual cell ; all its relations centre in the cell, 

 J ->t in the organ or complete individual — its function is formative. We go back a step farther, 

 where the granule is diffused matter, in a liquid, and we find nothing visible or tangible ; the 

 liquid then stands in the same relation to the granule that the granule does to the cell — or is it 

 unphilosophical to reason backward ? We certainly get into the region of conjecture, and all 

 we have to guide us is analogy. 



The granule is not a part of the cell. After the cell is formed, it may often be seen at- 

 tached to its walls. It is difficult, it is freely acknowledged, to conceive of the granule pro- 

 ducing cells destitute of vessels : all our conceptions of growth are formed from an apparatus 

 which is vascular ; but in animals, as well as vegetables, cells are formed without the aid of 

 vessels. The formation of ova and the epidermis are among the examples which may be 

 cited : we connect the animal and vegetable kingdoms together by this fact, the plant-like 

 growth of tissues and ova, or growth without the aid of vessels. It is the great discovery of 

 Schwak:-, that one common principle of development for the elementary particles, or granules, 

 prevailed in both the animal and vegetable tissues. The blood globules, or corpuscules, and 

 the muscular globules, are vesicles, or cells, of a common origin ; they each originate in a non- 

 vascular or structureless substance, and hence the primitive stage of existence in all organic 

 productions is alike. The essential characters of cells, in both kingdoms, is activity : this being 

 true of the individual, is also true of a combination ; activity preserves life, and life preserves 

 activity. The performance of the normal function constitutes health ; abnormal, disease ; ces- 

 sation, death. This activity, resident in a cell, determines the difference between an organized 

 molecule and an unorganized one, which may be seen in precipitates, which are often mem- 

 branous. The precipitated molecules perform no function — generate nothing, while the cell 

 granule, which is so analogous to a precipitate, does actually generate something by its force or 

 activity : hence a generating force is characteristic of organized matter. If granules are non- 

 vascular, how do they generate vesicles or cells'? By inhibition, matter is increased, and the 

 cell starts out, a membranous vesicle, from one side : cells coalesce and form fibres, tubes, 

 straight and spiral. The fibre is sometimes round and sometimes flat ; each form being pro- 

 duced by variation of circumstances. 



The form of cells, in both kingdoms, may be alike. For the construction of differently 

 shaped edifices, it is not necessary to use unlike elementary parts. All the varied forms of 

 crystals may originate from spheroids, and all the varied forms of organs may originate from 

 cells of the same form ; it is the diversified arrangement of molecules and of cells which give 

 rise to organs of different forms. In this the simplicity and economy of nature is manifested. 

 Nature, while she has all matter and means at her disposal, economises both. A muscular fibre 

 [Agkiccltural Repokt — Vol. m.] 26 



