ON MATTER AND FOECE. 89 



* 



Sulphate of thallium was also shown, by 

 spectrum-analysis, to pass into all the vascular 

 and non-vascular textures, and even sulphate 

 of silver was traced in almost every texture. 



In the Proceedings of the Royal Society, 

 April 12, 1866, Dr. Dupre and I further 

 showed that four grains of sulphate of quinine 

 passed in fifteen minutes into every texture 

 of a guinea-pig, and was detectable for forty- 

 eight hours. 



If we had sufficiently delicate modes of detect- 

 ing other substances, it can hardly be doubted 

 that they would follow the same law, and 

 be found to pass rapidly into every texture. 



With the matter, whatever energy that 

 matter possesses must pass also ; and wherever 

 the matter finds motions going on in which it 

 can take part, there the medicine will act. It 

 may be present in equal quantity elsewhere, 

 and yet give no sign of its presence, because 

 no increase or diminution of the motions in 

 those parts may occur. Let me illustrate this 

 for an instant by supposing a shower or sheet 

 of any substance fell in every part of this 

 room for example, alcohol. In many places 

 it would apparently not be present, no action 



