fHE CHEMISTRY OF FOOJ) 85 



23. The Sugars, or the Saccharine Substances. These con- 

 stitute the third and last group of the organic substances which 

 are employed as food. This group embraces, in addition to the 

 different kinds of Sugar, the varieties of starch and gum, from 

 whatever source derived. The two substances last named do 

 not, at first sight, present many points of similarity to sugar ; 

 but they closely resemble it in respect to their ultimate chem- 

 ical composition, being made up of the same elements, in nearly 

 the same proportions. And their office in the system is the 

 same, since they are all changed into sugar by the processes of 

 digestion. 



24. Sugar is chiefly of vegetable origin, the animal varieties 

 being obtained from honey and milk. The most noticeable 

 characteristic of this substance is its agreeable, sweet taste, 

 which makes it everywhere a favorite .article of food. But 

 this quality of sweetness is not possessed by all the varieties 

 of sugar in the same degree; that obtained from milk, for 

 instance, has a comparatively feeble taste, but rather imparts 

 a gritty feeling to the tongue. The other important properties 



9. The Effect of Climate on the Appetite. " Climate has an impor- 

 tant influence on the quantity of food demanded by the system ; and 

 every one has experienced in his own person a considerable difference at 

 different seasons of the year. Travelers' accounts of the amount of food 

 consumed by the natives of the frigid zone are almost incredible. They 

 speak of men eating a hundred pounds of meat in a day ; and a Russian 

 admiral, Saritcheff, mentions an instance of a man who, in his presence, 

 ate at a single meal a mess of boiled rice and butter weighing twenty- 

 eight pounds. Although it is difficult to regard these statements with 

 entire confidence, the general opinion is undoubtedly well founded that 

 the appetite is greater in cold than in warm climates. Dr. Hayes, the 

 Arctic explorer, states, from his own observation, that the daily ration of 

 the Esquimaux is from twelve to fifteen pounds of meat, about one-third 

 of which is fat. He once saw an Esquimau consume ten pounds of walrus 

 flesh and blubber at a single meal, which however lasted several hours, 

 with the thermometer 60 or 70 below zero. Some members of his own 

 party manifested a constant craving for fatty substances, and were in the 

 habit of drinking the contents of the oil-kettle with evident relish." 

 Flint's Physiology. 



23. Which are the third of the organic groups ? What do they embrace ? Points of 

 resemblance ? 



24. Origin of the sugars ? Ordinary sugar ? Beet-root? Maple-sugar? Grape-sugar? 

 Cane-sugar ? 



