PURE AND IMPURE FOODS. 



477 



accuracy are to be found recorded. A well 

 known case, remarks Dr. Carpenter, is that 

 of Thomas Wood, the miller, of Billericay, 

 reported to the College of Physicians in 

 1767, by Sir George Baker, in which a re- 

 markable degree of vigor is said to have 

 been sustained for upwards of 18 years on 

 no other nutriment than 16 ounces of flour 

 made into a pudding with water, no other 

 liquid of any kind being taken. In nutri- 

 tive value 16 ounces of flour will represent 

 1.72 ounces of nitrogenous matter, 0.32 

 ounce of fat and 11.28 ounces of .carbo- 

 hydrates. 



A more striking instance still is that af- 

 forded by the case of Cornaro, a Venetian 

 of noble descent, who lived in the 15th and 

 16th centuries, and attained an age upward 

 of 100. He became impressed with the con- 

 viction that the older a man gets and the 

 less power he possesses the less should be 

 the quantity of food consumed, in opposi- 

 tion to the common notion that more 

 should be taken to compensate for his fail- 

 ing power. He, therefore, at about 40 

 years of age, resolved to enter on a new 

 course, and betake himself to a spare diet 

 and scrupulously regular mode of life, 

 after having, as he says, previously led a 

 life of indulgence in eating and drinking, 

 and having been endowed with a feeble 

 constitution and "fallen into different kinds 

 of disorders, such as pains in my stomach, 

 and often stitches, and spices of the gout, 

 attended by what is still worse, an almost 

 continual slow fever, a stomach generally 

 out of order, and a perpetual thirst." He 

 also did all that lay in his power "to avoid 

 those evils which we do not find it so easy 

 to remove. These are melancholy, hatred, 

 and other violent passions, which appear to 

 have the greatest influence over our bodies. 

 The consequence was, that in a few days I 

 began,'' he adds, "to perceive that such a 

 course agreed with me very well ; and by 

 pursuing it, in less than a year I found my- 

 self (some persons perhaps will not be- 

 lieve it) entirely free from all my com- 

 plaints. I chose wine suited to my stomach, 

 drinking of it but the quantity I knQw I 

 could digest. I did the same by my meat, 

 as well as in regards to quantity and qual- 

 ity, accustoming myself so as to contrive 

 matters so as never to cloy my stomach 

 with eating or drinking ; but constantly to 

 rise from the table with a disposition to eat 

 and drink still more. In this I conformed 

 to the proverb which says that a man, to 

 consult his health, must check his appetite. 

 * * * What with bread, meat, the yolk 

 of an egg, and soup, I ate as much as 

 weighed in all 12 ounces, neither more nor 

 less. * * * I drank but 14 ounces of 

 wine." On this scanty allowance Cornaro 

 tells us he perseveringly subsisted ; and he 

 lived in possession of all his faculties to 

 write a series oi discourses at the respec- 



tive ages of 83, 86, 91 and 95, directed to- 

 wards urging others to follow a similar 

 course. These discourses, which are im- 

 bued with vigor and vivacity, and contain 

 many shrewd remarks on the subject of 

 living, seem to have excited considerable 

 attention at the time they appeared, and 

 for many years afterwards. 



THE DIGESTIBILITY OF FOODS. 



The value of food is determined not 

 alone by its composition, but also by its 

 digestibility ; that is, by the amount of it 

 which the body can retain and utilize as it 

 passes through the digestive tract. The 

 term digestibility as frequently employed, 

 particularly in popular articles, has several 

 other significations. Thus to many per- 

 sons it conveys the idea that a food agrees 

 with the user, i.e., that it does not cause 

 distress when eaten. The term is also 

 commonly understood to mean the ease or 

 rapidity of digestion, and one food is often 

 said to be more digestible than another 

 because it is digested in less time. How- 

 ever, the term digestibility is most com- 

 monly understood in scientific treatises on 

 the subject to mean thoroughness of di- 

 gestion. The digestibility of any food may 

 be learned most satisfactorily by experi- 

 ments with man, although experiments 

 are also made by methods of artificial 

 digestion. In the experiments with man 

 both food and feces are analyzed. De- 

 ducting the amounts of the several nutri- 

 ents in the feces from the total amount of 

 each nutrient consumed shows how much 

 of each was digested. The results are 

 usually expressed in percentages and spoken 

 of as coefficients of digestibility. From a 

 large number of experiments with man it 

 has been calculated that on an average the 

 different groups into which food may for 

 convenience be divided have the follow- 

 ing coefficients of digestibility: 



Carbo- Mineral 

 Foods Protein Fat hydrates matters 



Per cent. Per cent. Per cent. Per cent. 



Animal foods 98 97 100 75 



Cereals and sugars.. . 85 90 98 75 



Vegetables and fruits. 80 90 95 75 



Making use of these figures, the di- 

 gestible nutrients furnished by any food 

 may be readily calculated. Thus a table 

 of the composition of foods shows that 

 sirloin steak contains 16.5 per cent, pro- 

 tein. One and one-half pounds would 

 therefore contain 0.2475 pound protein, or 

 in round numbers, 0.25 pound (1.5 x 165 = 

 0.2475). As shown by the coefficients of 

 digestibility quoted above, 98 per cent, of 

 the protein of animal food is digestible. 

 Therefore, 1.5 pounds sirloin steak would 

 furnish 0.245 pound digestible protein 

 (0.25x0.98 = 0.245). The digestibility of 

 the several nutrients in a given quantity 

 of any food may be caJenlate4 in 3 similar 

 way, 



