the Nitrogenous Matter of Plants. 123 



more an organ is permeable to the air, and rich in nitrogenous 

 material, the less will be the quantity of starchy, oleaginous, and 

 saccharine products it accumulates. This circumstance may be 

 illustrated in the case of fibrils, young leaves, petals, stamens, 

 and the herbaceous stems of vegetables when forced to exuberant 

 growth by manures. The contrary obtains in proportion as the 

 contact with oxygen is lessened, as may be seen in fruits, seeds, 

 and bulky roots, all which are structures in which we find those 

 starchy and cognate alimentary matters in greater or smaller 

 quantity, or artificially accumulated in still larger proportions 

 by preserving some portions of the plants from contact with the 

 air (e. g. potato and beetroot) . 



The action exercised by the proteine matter on the pabulum 

 for respiration, though at first having a contrary purpose, has 

 nevertheless, when of a certain intensity, the tendency to shorten 

 the duration of the organ in which it proceeds, or at least to 

 diminish its consistence. For example, young fibrils, petals, 

 stamens, fungi, &c., rapidly wither ; and the stems of flax and of 

 our cereals, when their growth is too much forced by highly 

 nitrogenous or too abundant manure, become overturned and 

 laid on the ground from the insufficiency of those cellulose and 

 encrusting deposits to which under ordinary conditions they are 

 indebted for the powers of resistence to the influence of the rain 

 and wind. 



The conclusions deducible from the facts set forward in this 

 memoir are, that the living azotized matter seen in motion 

 within the cells of plants unites in itself the principal attributes 

 of that which enters into the nature of animal life : it possesses 

 the like excitability, contractility, and elementary composition ; 

 its respiration, in all that concerns its more appreciable results, 

 differs in no way from that of animals. But whilst the proteine 

 matter of plants possesses in itself the composition and some of 

 the principal functions of that found in the superior animals, it 

 likewise possesses an assimilating force not met with except 

 among the lowest animals, whereby it brings inorganic matters 

 into connexion with its own proper substance and with that of 

 animals. 



[^Observations. — The foregoing essay evinces much diligent 

 micro-chemical research, and furnishes a valuable contribution 

 to our knowledge of the internal economy of plant-cells. But, 

 whilst acknowledging thus much, we are not disposed to accept 

 the writer's interpretation of much that he describes. The 

 marvellous internal arrangement of vessels, carrying on a circu- 

 lation of fluid, radiating from the nucleus and forming a net- 

 work in the primordial tunic communicating with a similar vas- 



