DIGESTIBILITY OF FOOD. 323 



questions which it behoves the physician to determine, and which 

 do not fall within the province of physiological chemistry. The 

 latter science merely furnishes the physician with the fixed prin- 

 ciples or scientific means necessary for enabling him to arrive at a 

 more exact knowledge of carefully observed practical facts on 

 which to base a system of dietetics. Until the appearance of 

 Moleschott's admirable work,* most of the treatises on dietetics 

 consisted merely of individual physiological facts carelessly con- 

 nected with more or less well-grounded propositions ; and while 

 they were deficient in a logically strict treatment of these different 

 propositions, they did not even give those minute observations 

 with which many of the older practitioners had enriched the theory 

 of dietetics ; not unfrequently, indeed, we meet with an entire con- 

 founding of the ideas of digestibility, nutritive power, and the 

 facility with which different articles of food can be borne. Such 

 a proper elaboration of dietetics does not, however, fall within the 

 province of physiology, but belongs exclusively to the practical 

 physician. 



We cannot avoid offering a few remarks on certain miscon- 

 ceptions which we occasionally meet with in reference to the 

 value of physiological chemistry, in relation to Pathology and 

 Therapeutics. Although we have endeavoured throughout the 

 present work to draw attention to the deficiency of our knowledge, 

 to refer all views and assertions to their true foundation, and to 

 check as far as possible the haste with which individual observa- 

 tions or discoveries have been applied to practice, we have been 

 anxious to avoid those hasty and uncharitable judgments which 

 we meet with from time to time both in literature and in medical 

 practice. Physiological Chemistry has recently done more in 

 destroying former illusions, than in furnishing physicians with 

 new materials for further hypotheses. We may, indeed, instance 

 many discoveries in Physiological Chemistry which have exerted 

 a direct influence on medical practice, but the great number of 

 deficiencies which still exist in this respect, hold out a prospect of 

 ample return to future labourers. It is not the province of 

 Physiological Chemistry, as a special department of science and a 

 branch of physiology, to guide the physician within narrow limits 

 by which he must bound his own reflections and investigations, 

 and regulate his practice ; for our science presents too many 

 deficiencies within its own domain to enter upon a foreign pro- 

 vince, whose possession has already caused strife and jealousy. 

 * Physiologic d. Nahrungsmittel. Darmstadt, 1850. 



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