THE NUTRITIVE VALVE OF DIFFERENT FOODS. 119 



which they eat. Such tribes are, however, said to suffer 

 especially from intestinal parasites; and there is no doubt 

 that to many animals as well as most men the absence of 

 salt from their diet is a terrible deprivation. Buffaloes and 

 other creatures are well known to travel miles to reach 

 " saltlicks;" of two sets of oxen, one allowed free access to 

 salt, and the other given none save what existed in its or- 

 dinary food, it was found after a few weeks that those given 

 salt were in much better condition. In man the desire for 

 salt is so great that in regions where it is scarce it is used as 

 money. In some parts of Africa a small quantity of salt will 

 buy a slave, and to say that a man commonly uses salt at his 

 meals is equivalent to stating that he is a luxurious mill- 

 ionaire. In British India, where the poorer natives regard 

 so few things as necessaries of life that it is hard to levy any 

 excise tax, a large part of the revenue is derived from a salt 

 tax, salt being something which even the poorest will buy. 

 As regards Europe, it has been found that youths in the 

 Austrian empire who have fled to the mountains and there 

 led a wild life to avoid the hated military conscription, will, 

 after a time, though able abundantly to supply themselves 

 with other food by hunting, come down to the villages to 

 purchase salt, at the risk of liberty and even of life. 



The Nutritive Value of Different Foods. All meats, 

 whether derived from beast, bird, or fish, are highly valu- 

 able foods. They contain abundant albumen, more or less 

 fat, and, when cooked, their connective tissue is in great part 

 turned into gelatin. Pork is the least easily digested form 

 of fresh meat, and contains a larger percentage of fat than 

 most. This fat, which, by its oxidation liberates much 



Give illustrations of the strength of the desire for salt. 

 Why are meats valuable foods? How does pork differ from other 

 fresh meats? Why is pork not a good form of food for summer? 



