64 ON THE STUDY OF PHYSIOLOGY. 



Chemical researches into the composition of the fluids 

 and solids of the animal frame, and comparative examina- 

 tions of them under tlie differences of age, sex, climate, 

 food, mode of life, and the various incidences of disease, 

 have thrown great light both on the healthy and disordered 

 actions of our frame : particularly those inquiries which 

 have been conducted with the advantages of the modern 

 improvements in chemical science. Further benefit is to be 

 expected from a continuance of these exertions ; and we 

 can have no hesitation in admitting that many important 

 points in physiology cannot be understood, the nature and 

 result of many animal processes cannot be appreciated, by 

 a person unacquainted with chemistry. 



Nor is the benefit confined to physiology ; the kindred 

 sciences, which have for their object the knowledge of dis- 

 ease, its prevention and cure, owe great and important 

 obligations to modern chemistry. By unfolding the com- 

 position, and separating the various Ingredients contained in 

 an apparently homogeneous fluid, the urine, it has enabled 

 us to form some conception of the important purposes 

 executed by the kidney. By shewing the deviations which 

 this animal fluid exhibits in various conditions of disease, 

 it has elucidated the mechanism of many disordered ac- 

 tions ; and, by discovering what particular ingredients ex- 

 isted in undue proportion, it has suggested the means of 

 relief by the internal administration of suitable ehemical 

 remedies. Thus the modern views respecting the nature 

 and treatment of calculous disorders are completely che- 

 mical ; and modern experience fully substantiates the im- 

 portant truth, that alkalies and acids taken into the sto- 

 mach affect the chemical constitution of the urinary secre- 

 tion. But these views do not terminate here : the condi- 

 tion of the urine is an index of what is going forwards in 

 the alimentary canal, an outward and visible sign of the 

 inward and hidden movements of the stomach, bowels, and 

 other parts. These again are variously modified by the 

 nature and quality of our food and drink, by the operation 

 of our remedies, and by those obscure and mysterious, but 



