1897.] Dr. H. A. Cummins — A Theory of Vegetable Antitoxins. 21 



trees, especially those in the process of transpiration, has been explained. 

 To combat these organisms it is probable that the roots exude a part cf 

 the poisonous principle into the surrounding soil. 



Change of locality frequently alters the power of many organisms 

 which cause disease in man, so we may infer that the absence or varia- 

 tion in quantity of secretion is due to the necessary organisms being 

 absent altogether or present in small numbers. 



From a consideration of all the foregoing circumstances, it seems 

 to me almost certain that organisms do gain admission to the vascular 

 systems of plants. The irritation which they produce on the cells 

 causes the formation of antitoxins and these antitoxins are many of the 

 alkaloids and useful vegetable drugs which are constantly employed as 

 medicinal remedies and for other purposes. These may exist in the 

 plant in the form in which we know them or in a state, a very slight 

 change from which by the action of a ferment, converts them into 

 substances capable of protecting the cells or into their known condition. 

 The peculiarities of protoplasm in different species have been noted 

 and it seems possible for one kind of protophyte to produce toxins 

 having different characters in different plants. 



It is a noticeable fact that many toxic substances are obtained from 

 the bark through the inner layers of which albuminoids are carried. 



Conclusion — Fermentative parasites gain admission to the tissues 

 of the plant : the irritation produced causes a reaction in the cells of the 

 host ; this reaction results in the formation of a protective substance, 

 an antitoxin ; and this latter causes the death of the parasite. 



In connection with this paper Dr. Prain said : — 



Dr. Cummins' theory is a very interesting one, carefully thought 

 out and clearly stated. It is at the same time more or less conjectural 

 and some of the facts cited in support of certain of the steps in the 

 reasoning may be said to be, if not contradictory, at all events not 

 corroborative. Two of these may be mentioned as examples. 



In the chapter on Antiseptics it is said that Eucalyptus globulus is 

 well known as a purifier of the soil and it is probable that the essential 

 principle of the oil is antitoxic. The 5faieme?i^ is very well known and 

 is perhaps often believed, but I most certainly do not think either that 

 the case for the Eucalyptus has been made out or that the benefits 

 derived from its culture are greater than would be attained if another 

 tree were planted, which in Dr. Cummins' own words (in Sect. V.) is 

 capable of transpiring moisture equal to eleven times the rainfall over 

 the area covered by the foliage of the tree. 



If the citation of Cannabis sativa var. indica be intended to imply 

 that its secretion of resin in Bengal is at all a protective measure, 1 have 



