232 ZOOLOGICAL PHILOSOPHY 



cellular tissue more or less modified by the movement of fluids, a tissue 

 which is very slightly modified in the algae, fungi and even the mosses, 

 whereas it is much more modified in the other plants and especially 

 in the dicotyledons. But everywhere, even in the most perfect animals, 

 there is really nothing in their interior but a cellular tissue modified 

 into a large number of different tubes, most of which are parallel to 

 one another in consequence of the ascending and descending move- 

 ment of the fluids. Yet the structure of these tubes is not comparable 

 to that of the vessels of animals which possess a circulatory system. 

 Nowhere do these vegetable tubes intertwine or form those special 

 groups of vessels, folded and interlaced in infinite variety, that we call 

 conglomerate glands in animals which have a circulation. Finally 

 in all plants without exception, there is no special organ within their 

 bodies : there is nothing but more or less modified cellular tissue, 

 longitudinal tubes for the movement of fluids, and harder or softer 

 fibres also longitudinal, for strengthening the stem and branches. 



If we admit on the one hand that every living body whatever is a 

 mass of cellular tissue, in which are embedded various organs of a. 

 number proportionate to the complexity of organisation ; and if on 

 the other hand we also admit that all bodies contain within them fluids 

 that move faster or slower according as the state of organisation 

 allows of a more or less active or energetic hfe, we are forced to the 

 conclusion that it is to the movement of fluids in the cellular tissue 

 that we have primarily to attribute the formation of every kind of 

 organ in the midst of this tissue, and hence that each organ must be 

 invested by it both in its gross outhnes and in its most minute parts, 

 as indeed we actuaUy find. 



With regard to animals, I have no need to show that in various of 

 their internal parts the cellular tissue is squeezed aside by the moving 

 fluids, which open a passage through it ; and that in these regions 

 it has been forced back upon itself ; it has then been compressed and 

 transformed into investing membranes round about these running 

 streams of fluid ; while on the outside these Uving bodies are inces- 

 santly compressed by the environing fluids (either water or atmospheric 

 fluids) and modified by external impressions and by deposits upon 

 them. Their cellular tissue has thus come to form that universal 

 investment of every living body, that is called skin in animals and 

 bark in plants. 



I was then fully justified when I said " that the function of the move- 

 ment of fluids in the supple parts of living bodies, and especially in 

 the cellular tissue of the simplest among them, is to carve out routes, 

 places of deposit and exits, to create canals and thereafter diverse 

 organs, to vary these canals and organs in accordance with the 



