128 ADDITIONAL NOTES. 



that various deleterious (as well as medicinal) 

 agents of vegetable origin, when administered in- 

 ternally, also affect the vital organs in the same 

 manner, by entering the vascular system, and 

 being mixed with the circulating blood. 



But I have further stated, that there is much 

 reason to believe that some of the more active 

 poisons operate in a different manner, and that 

 when applied to mucous membranes they are 

 capable of affecting the nervous centres through 

 the medium of the nerves, and independently of 

 absorption. 



On this last point, other physiologists have 

 arrived at a different conclusion, and are of 

 opinion that even those poisons which are the 

 most active, and which seem to produce their 

 effect almost instantaneously, do so, not by an 

 influence transmitted through the nerves, but 

 solely by penetrating the solid tissues, and thus 

 contaminating the blood. 



The arguments in favour of this view of the 

 subject have been well stated by Mr. Blake, in a 

 memoir published in the 53rd volume of the 

 Edinburgh Medical and Surgical Journal. They 

 are founded on the facility with which the tissues 

 are penetrated by fluid and gaseous bodies, and 

 on the great rapidity of the circulation. 



The facts advanced by Mr. Blake are equally 

 interesting and important. There can be no 

 doubt that poisons applied to the tongue may 

 enter into the blood in a very short space of 

 time; and that this must at any rate be one mode 



