298 AN AMERICAN TEXT-BOOK OF [PHYSIOLOGY. 



too uncertain to permit any re"sum6 to be given here. When alcohol is taken 

 in excess it produces the familiar symptoms of intoxication, which may pass 

 subsequently into a condition of stupor or even death, provided the quantity 

 taken is sufficiently great. So, also, the long-continued use of alcohol in large 

 quantities is known to produce serious lesions of the stomach, liver, nerves, blood- 

 vessels, and other organs. The effect of alcohol upon the body evidently varies 

 greatly with the quantity used. It may perhaps be said with safety that in small 

 quantities it is beneficial, or at least not injurious, barring the danger of acquiring 

 an alcohol habit, while in large quantities it is directly injurious to various tissues. 



Condiments and Flavors. These substances probably have a directly bene- 

 ficial effect on the processes of digestion by promoting the secretion of saliva, 

 gastric juice, etc., in addition to the important fact that they increase the pal- 

 atableness of food, and hence increase the desire for food. With reference to 

 the condiments, Brandl has shown, in the paper referred to on p. 252, that mus- 

 tard and pepper also markedly increase the absorption of soluble products from 

 the stomach. 



Conditions Influencing Body-metabolism. In considering the influence 

 of the various food-stuffs upon body-metabolism we have for the most part 

 neglected to mention the effect of changes in the condition of the body. It 

 goes without saying that such things as muscular work, sleep, variations in 

 temperature, etc. have or might have an important effect upon the character 

 and amount of the chemical changes going on in the body, and in conse- 

 quence a great many elaborate investigations have been made to ascertain pre- 

 cisely the effect of conditions such as those mentioned upon the amount of 

 the excretions, the production of heat in the body, and other similar points 

 which throw light upon the nature of the metabolic processes. 



Effect of Muscular Work. It is a matter of common knowledge that mus- 

 cular work increases the amount of food consumed, and therefore the total 

 body-metabolism, but it has been a point in controversy whether the increased 

 oxidations affect the proteid or the non-proteid material. According to Liebig, 

 the source of the energy of muscular work lies in the metabolism of the proteid 

 constituents, and with increased muscular work there should be increased de- 

 struction of proteid and an increase in the nitrogenous excretions. That the 

 total energy of muscular work is not derived from the oxidation or metabolism 

 of proteid alone was clearly demonstrated by the famous experiment of Fick 

 and Wislicenus. These physiologists ascended the Faulhorn to a height of 

 1956 meters. Knowing the weight of his body, each could estimate how much 

 work was done in ascending such a height. Fick's weight, for example, w r as 

 66 kilograms, therefore in climbing the mountain he performed 66 X 1956 = 

 129,096 kilogrammeters of work. In addition, the work of the heart and the 

 respiratory muscles, which could not be determined accurately, was estimated 

 at 30,000 kilogrammeters. There was, moreover, a certain amount of muscular 

 work performed in the movements of the arms and in walking upon level 

 ground that was omitted entirely from their calculations. For seventeen hours 

 before the ascent, during the climb of eight hours, and for six hours afterward 



