Observations and Experiments on Opium. 1 7 



matter differently endowed, from that in which the change 

 is observed. 



"Has not Dr. Hare committed a mistake in understanding Sir 

 Humphrey Davy to assert that heat is motion ; whereas, his doc- 

 trine is, that motion is the cause of heat." 



The author forgets that the word heat is used to signify a 

 cause as well as an effect ; when I have spoken of motion 

 as substituted for heat, I meant that it was substituted for the 

 cause of sensible heat. The phenomenon which we call 

 sensible heat, is the effect of motion according to one hy- 

 pothesis of caloric, or latent heat according to the other. 

 It appears, therefore, that when correctly examined, the de- 

 finition which I have given of Davy's hypothesis is the same 

 as that which the author sanctions. 



To conclude, I regret that instead of having only to en- 

 counter difficulties inherent in the subject, I should be obli- 

 ged to occupy so many pages in refuting criticisms, respecting 

 which, I can sincerely say in the author's own language, that 

 they are " idle" and have " no bearing whatever'''' upon the 

 subject, which has called them forth. 



Art. III. — Observations and Experiments on Opium; by 

 George W. Carpenter, of Philadelphia. 



OPIUM, 



Its varieties and appearance in commerce, fyc. 



This important article, from its extensive usefulness, in 

 modifying and alleviating the most afflicting and painful dis- 

 eases, incident to human nature, merits perhaps the most 

 conspicuous place in the materia medica, and yet from the 

 frequent abuse by injudicious administration, and more par- 

 ticularly, from improper pharmaceutical preparations, pro- 

 duces many injuries and distressing consequences. It is 

 therefore an important inquiry to discover the causes of these 

 inconveniences. For this end I have made a series of exper- 

 iments, and am happy to submit the result, in the following 

 observations. Before however, immediately entering upon 

 the pharmaceutical preparations, it may not perhaps be im- 

 proper to offer a very concise view of the natural history and 

 physical characters of this article, as it occurs at the present 

 day in our commerce. 



Vol. XIIL— No. 1. 3 



