HUNGER AND THIRST. 175 



opening into the oesophagus of a horse, tied the lower portion, and allowed the animal 

 to drink after he had been deprived of water for a number of hours. The animal drank 

 an immense quantity, but the water did not pass into the stomach, and the thirst was 

 not relieved. He modified this experiment by causing dogs to drink with a fistulous 

 opening into the stomach by which the water was immediately discharged. They con- 

 tinued to drink without being satisfied, until the fistula was closed and the water could 

 be absorbed. We have often repeated the latter experiment in public demonstrations. In 

 one of these particularly, the animal drank repeatedly until he had taken several quarts 

 of water, only ceasing from fatigue and soon recommencing ; but, so soon as the fistula 

 was closed, he drank a moderate quantity and was satisfied. 



In a case reported by Dr. Gairdner, of Edinburgh, in the human subject, all the 

 liquids swallowed passed out at a wound in the neck by which the oesophagus had been cut 

 across. The thirst in this case was insatiable, although buckets-full of water were taken in 

 the day ; but, on injecting water, mixed with a little spirit, into the stomach, the sen- 

 sation was soon relieved. This observation was made in 1820, long before the experi- 

 ments just referred to upon the inferior animals. 



Although the sensation of thirst is referred to special parts, it is an expression of the 

 want of fluids in the system and is to be effectually relieved only by the absorption of 

 fluids by the blood. There are no nerves belonging to. the cerebro-spinal system which 

 have the office of carrying this sensation to the brain, division of which will abolish the 

 desire for liquids. Experiments show that no effectual relief of the sensation is afforded 

 by simply moistening the parts to which the heat and dryness are referred. As a demand 

 on the part of the system, it is entirely analogous to the sense of want of air and of 

 hunger, differing only in the way in which it is manifested. 



After a certain period of inanition, febrile movement and general agitation occur, 

 and there is almost always disturbance of the mental faculties, amounting sometimes to 

 furious delirium. Frequently, however, the delirium is of a mild character, with hallu- 

 cinations. There are cases in which there is no marked mental disturbance, but these 

 are generally in persons who voluntarily suffer starvation. 



The length of time that life continues after complete deprivation of food and drink is 

 very variable. The influences of age and obesity have already been referred to. With- 

 out citing the numerous individual instances of starvation in the human subject which 

 have been reported, it may be stated, in general terms, that death occurs after from five 

 to eight days of total deprivation of food. In 1816, one hundred and fifty persons, 

 wrecked on the frigate Medusa, were exposed on a raft in the open sea for thirteen days. 

 At the end of this time only fifteen were found alive. One of the survivors, M. Savigny, 

 gave, in an inaugural thesis, a very instructive and accurate account of this occurrence, 

 which has been very generally quoted in works of physiology. Authentic instances are 

 on record in which life has been prolonged much beyond the period above mentioned ; but 

 they generally occurred in persons who were so situated as not to suffer from cold, 

 which the system, under this condition, has very little power to resist. In these cases, 

 also, there was no muscular exertion, and water was generally taken in abundance. All 

 of these circumstances have an important influence in prolonging life. 



Berard quotes the example of a convict who died of starvation after sixty-three days, 

 but in this case water was taken. An instance of eight miners who survived after five 

 days and sixteen hours of almost complete deprivation of food is referred to in works 

 upon physiology. Berard also quotes from various authors instances of deprivation of 

 food for periods varying from four months to sixteen years; but these accounts are not 

 properly authenticated and are discredited by physiologists. They generally occurred in 

 hysterical females, and their consideration belongs to psychology rather than to physi- 

 ology. According to Chossat, death from starvation occurs after a loss of four-tenths of 

 the weight of the body, the time of death being variable in different classes of animals. 



From thirty to thirty-five days may be taken as the average duration of life in dogs 



