ON ORGANIC CHEMISTRY. 51 



formation of calculi ; a subject upon which, for obvious reasons, we cannot 

 enter. In fact, in this second part of his report, all the most interesting 

 transformations of the food of the various organs and tissues of the body are 

 discussed with his usual success. Whilst examining the action of organic 

 remedial agents on the animal ceconomy, he touches upon the use of tea and 

 coffee as an article of food ; and as this is a subject of very general interest, 

 we will briefly state his opinions. 



It is well known that recent chemical research has proved the fact, which 

 the boldest imagination dared not have ventured to conceive, that the active 

 principles of tea and coffee, viz. theine and caffeine, are absolutely one and the 

 same body, being perfectly identical in every respect. The presence of this 

 iu two vegetables belonging to different natural families, and derived from 

 different quarters of the globe, proves that the action of tea and coffee on the 

 system must be the same. Some cause there must be to explain how the 

 practice of taking them has become a necessary of life to whole nations. 

 Now caffeine (theine) is a highly nitrogenized body. Bile, it is well known, 

 contains an essential nitrogenized ingredient, taurine. Now Professor Liebig 

 considers that caffeine goes to the production of this taurine ; and by calcu- 

 lating the formulas of both, he shows, that if nine atoms of water and nine 

 atoms of oxygen be added to the formula of caffeine, we obtain the formula 

 of two atoms of taurine. Two and eight-tenths of a grain of caffeine is sufficient 

 to form the taurine contained in one ounce of bile ; and if we admit that the 

 infusion of tea consumed contained no more than one-tenth of a grain of caf- 

 feine, still if it contribute in point of fact to the formation of bile, the action 

 even of such a quantity cannot be looked upon as nullity. 



Neither can it be denied, that in case of using an excess of non-azotized 

 food, or deficiency of motion, which is required to cause the change of matter 

 in the tissues, and thus to yield the nitrogenized matter of the bile ; that in 

 such a condition the state of health may be benefited by the use of tea or 

 coffee, by which may be furnished the nitrogenized product produced in the 

 healthy state of the body, and essential to the production of an important 

 element of respiration. It is only in a chemical sense that these remarks are 

 intended to show, that such compounds as caffeine or theine, asparagine and 

 theobromine, are better adapted to this purpose than all other vegetable 

 principles. 



The American Indian, with his present habits of living solely on flesh, 

 could not with any comfort use tea as an article of food, for his tissues waste 

 with such rapidity, that, on the contrary, he has to take something to retard 

 this waste. And it is worthy of remark, that he has discovered in tobacco 

 smoke a means of retarding the change of matter in the tissues of his body, 

 and thereby of making hunger more endurable ; and that he cannot with- 

 stand the captivation of brandy, which, acting as an element of respiration, 

 puts a stop to the change of matter by performing the function which pro- 

 perly belongs to the products of the metamorphosed tissues. With the Indian 

 savages, brandy administers to their feelings of comfort, which tea in their 

 cases would not do. 



The third part of Professor Liebig's report treats of the recondite laws of 

 the phenomena of motion. His observations on these fully bear out the high 

 character of the other parts of the report ; but as they require more detail iu 

 order to be understood, we can better afford to shorten our abstract by 

 merely referring to the report itself. 



The Professor concludes his valuable communication by two chapters, one 

 on the Theory of Disease, the other on the Theory of Respiration. With a 

 very few words on these subjects, we will close this abstract. 



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