FOODS. 325 



bottle " men who drank their port-wine after a heavy dinner, 

 got off far more safely than the modern tippler who is taking 

 ''nips" all day long, although the latter may imbibe a 

 smaller quantity of alcohol in the twenty-four hours. By far 

 the best way, however, is to avoid alcohol altogether in health. 

 If the facts lead us to conclude that under some conditions 

 it may be to a certain extent a food, it is a dangerous one: 

 even in what we may call "physiological " quantities, or such 

 amounts as can be totally oxidized in the Body. 



The Advantage of a Mixed Diet. The necessary quan- 

 tity of daily food depends upon that of the material daily lost 

 from the Body, and this varies both in kind and amount with 

 the energy expended and the organs most used. In children 

 a certain excess beyond this is required to furnish materials 

 for growth. Although it is impossible to lay down with per- 

 fect accuracy how much daily food any individual requires, 

 still the average quantity may be derived from the table of 

 daily losses given on page 300, which shows that a healthy 

 man needs daily in assimilable forms about 274 grams (4220 

 grains) of carbon and 19 grams (292 grains) of nitrogen. 

 The daily loss of hydrogen, which is very great (352 grams 

 or 5428 grains), is for the most part made good by water which 

 has been drunk and, so to speak, merely filtered through the 

 Body, after having assisted in the solution and transference 

 through it of other substances. About 300 grams (4620 

 grains) of water containing 33.3 grams (513 grains) of hy- 

 drogen are, however, formed in the Body by oxidation, and 

 the hydrogen for this purpose must be supplied in the form 

 of some oxidizable foodstuff, whether proteid, fat, or carbo- 

 hydrate. The oxygen eliminated is mainly received from the 

 air through the lungs, but some is taken in combination in 

 the food. 



Since proteid foods contain carbon, nitrogen and hydro- 

 gen, life may be kept up on them alone, with the necessary 

 salts, water and oxygen; but such a form of feeding would 

 be anything but economical. Ordinary proteids contain in 

 100 parts (p. 9) about 52 of carbon and 15 of nitrogen, so a 

 man fed on them alone would get about 3| parts of carbon 

 for every 1 of nitrogen. His daily losses are not in this ratio, 

 but about that of 274 grams (4220 grains) of carbon to 20 

 grams (308 grains) of nitrogen, or as 13.7 to 1; and so to get 

 enough carbon from proteids far more than the necessary 



