OF MALARIA. 29 



position merely of certain vegetables, forms or diversifies 

 miasmata. " Thus," says McCulloch, "might the cruci- 

 form plants, OR THE TRIBE OF FUNGI, produce a malaria 

 differing from that poison as resulting from the gramine- 

 ous ones, or the consequence of the putrefaction of seeds 

 differ from that of leaves." Some French writers lay 

 great stress on the influence of narcotic vegetables in the 

 causation of malaria. 



McCulloch, after a very elaborate citation of facts and 

 opinions, arrives at the indefinite conclusion "that the pre- 

 sence of vegetables or vegetable matter, in some mode or 

 form, is necessary to the extrication of malaria; while the 

 conclusion has sometimes been, that it is a production 

 formed between the living vegetable and water: more 

 generally that it is generated between that and the latter, 

 in some stage intermediate between life and absolute de- 

 composition', or, lastly, that it is the consequence of abso- 

 lute putrefaction." 



I need scarcely say that the ifs and ands, and buts and 

 ors, in McCulloch's book, show the utter inefficiency of his 

 undefined cause, to explain the difficulties of this vexed 

 question. Nor is it necessary to offer objections to the 

 other theories cited, since no one has sustained them by 

 even plausible reasoning or pertinent facts. They are not 

 received or respected by the ' profession.' 



The last of the theories to which I shall invite your at- 

 tention, are those of Drs. Ferguson and Robert Jackson. 



The latter gentleman, once a firm believer in malaria as 

 usually understood, saw, during his West India service, so 

 many antagonistic phenomena as to incline him to the opi- 

 nion, that it is, sometimes at least, an emanation from liv- 

 ing vegetables, through the exuberance of organic life, the 

 excess of vital vegetable action. To use his own language, 



3* 



