1897.] Dr. H. A. Cummins — A Theory of Vegetable Antitoxins. 17 



We can imagine without difiSculty the converse of this case ; 

 hostile organisms gaining admission and damaging the tissue by causing 

 fermentations. The host plant then throws out an antitoxic flaid from 

 its cells to save it from destruction. 



The possibility of entrance of protophytes is made easier of belief 

 wlien we also think that colouring matter can pass the epidermal cells 

 of the root and get carried through the vascular system of the plant 

 to the flowers. 



Sec. II. Unorganised Ferments — Comparison between physiological 



PROCESSES in animal AND VEGETABLE CELL. 



In the next place we must consider the points of analogy in the 

 physiological processes of the animal and vegetable cell. 



We find that in the vegetable cell, starch is converted into glucose 

 or cane-sugar. This change is said to be due to the action of an un- 

 organized ferment and of this class of ferments several have been shown 

 to occur, viz. — Emulsin in almonds, diastase in barley, and myrosin in 

 mustard seeds. A similar change of starch into sugar takes place in 

 human saliva and by the action of pancreatic juice. Again a peptic 

 ferment changes, in the vegetable cells, the reserve proteids into 

 peptones (Sachs, op. cit., page 708). The leaves of Drosera produce 

 an acid and a ferment which act on albuminous compounds like pepsin. 

 This is also the case with the secretion of the leaves of butterwort 

 (Pinguicula) which act in a manner similar to the gastric juice of 

 animals, (Kerner, op. cit., pages 142 and 144). Asparagin which is a 

 bye product in the oxidation of nitrogenous substances of the plant 

 has been said to correspond physiologically with urea in animals 

 (Sachs, op. cit., page 722). 



In comparing circulatory systems of plants and animals, we find 

 in the latter arteries, veins, lactiferous vessels, &c., for the conveyance 

 of special nutritive fluids. In the former (plants) the circulation of 

 sap takes place thus : — In the parenchyma of the fundamental tissue 

 which has an acid reaction, are conveyed carbo-hydrates and oil : by the 

 soft bast the albuminoids which have an alkaline reaction. When there 

 are lactiferous vessels they furnish an open communication between all 

 the organs of the plant. These lactiferous vessels contain albuminoids, 

 carbo-liydrates and oil as well as poisons and other secondary products 

 of metastasis. Of the secondary products of metastasis such as colour- 

 ing matters, acids, alkaloids, &c., many have no known physiological 

 signification in the life of the plant (Sachs, op. cit., pages 706, 711- 

 712.) 



Again some gases as sulphuretted hydrogen, carbon oxide, commoa 



