ON ORGANIC CHEMISTRY. 45 



have been born. In cold regions, the food must contain a greater quantity 

 of carbon, or, in other words, be more combustible. 



The Englishman in Jamaica perceives with regret the disappearance of his 

 appetite, which in England had been a constant recurring source of enjoy- 

 ment. By the use of aromatics he creates an artificial appetite, and eats as 

 much food as he did at home. But he thus unfits himself for the climate 

 in which he is placed ; for sufficient oxygen does not enter his system to 

 combine with the carbon contained in the food, and the heat of the climate 

 prevents him from taking exercise to increase the number of his respirations : 

 the carbon of the food is therefore forced into other channels, and disease 

 results. 



England, on the other hand, sends her dyspeptic patients to southern cli- 

 mates. In our own land, their impaired digestive organs are unable to fit the 

 food for that state in which it best unites with the oxygen of the air, which 

 therefore acts on the organs of respiration themselves, thus producing pul- 

 monary complaints. But when they are removed to warmer climates they 

 absorb less oxygen and take less food, and the diseased organs of digestion 

 have sufficient powers to place the diminished amount of food in equilibrium 

 with the respired oxygen. 



Just as we would expect from these views, in our own climate hepatic dis- 

 eases, or diseases arising from an excess of carbon, are more prevalent in 

 summer ; and in winter pulmonic diseases, or those arising from an excess of 

 oxygen. 



The cooling of the body, by whatever means it may be produced, implies 

 a greater demand for food. Violent exercise, loud and long-continued speak- 

 ing, the crying of infants, moist air, all exert an appreciable influence on the 

 amount of food which is taken. 



The whole process of respiration appears most clearly developed in the 

 case of a man exposed to starvation. 



32|- oz. of oxygen enter into his system daily, which never again escape, 

 except in combination with parts of his body. Currie mentions the case of 

 an individual who was unable to swallow, and whose body lost 100 lbs. in 

 weight in one month ; and Martell, in the Transactions of the Linnean So- 

 ciety, recounts the case of a fat pig, overwhelmed in a slip of earth, which 

 lived for 160 days without food, and had diminished in weight during that 

 time 120 lbs. The history of the hybernating animals and of those which 

 acquire a periodical accumulation of fat, proves that the oxygen of the air 

 readily combines with the carbonaceous matters ; whilst in their winter 

 sleep they may be considered in the light of a lamp slowly burning, the oil 

 or fat for which has been stored up in sufficient quantity to sustain the com- 

 bustion, that is, the animal heat ; for nutrition, properly so called, does not 

 proceed in these animals during winter. The more fat then an animal con- 

 tains, the longer will it be able to exist without food, for that will be con- 

 sumed before the oxygen of the air acts upon the other parts of the body. 



From all this it will be seen, that in Liebig's view respiration is the fall- 

 ing weight, the bent spring which keeps the clock in motion; the inspirations 

 and expirations are the strokes of the pendulum which regulate it. In our 

 ordinary time-pieces we know with mathematical accuracy the effect pro- 

 duced on their rate of going, by changes in the length of the pendulum, or 

 in the external temperature. Few, however, have a clear conception of the 

 effect of air and temperature on the health of the human body ; and yet the 

 research necessary for keeping it in the normal state is not more difficult 

 than in the case of a clock. 



No one can deny that the nerves have considerable influence in the re- 



