142 ALIMENTATION 



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

 expression of the want of liquids in the system and is to be effectually 

 relieved only by their absorption by the blood. There are no nerves 

 belonging to the cerebro-spinal system that have the office of conveying 

 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 analogous 

 to the sense of want of air and of hunger, differing only in the manner 

 in which it is manifested. 



The duration of life after complete deprivation of food and drink is 

 variable. The influence of age has already been referred to. Taking 

 no account of certain remarkable individual instances of starvation in 

 the human subject that have been reported, it may be stated, in general 

 terms, that death occurs within five to eight days after total deprivation 

 of food. In the instance of the one hundred and fifty persons wrecked 

 on the frigate Medusa, in 1816, who were exposed on a raft in the open sea 

 for thirteen days, only fifteen were found alive. Dr. Savigny, one of 

 the survivors, gave, in an inaugural thesis, an instructive and accurate 

 account of this occurrence, which has often been quoted in works on 

 physiology. Authentic instances are on record in which life has been 

 prolonged much beyond the period above mentioned ; but they usually 

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

 which the system, under this condition, has but little power to resist. In 

 these cases, also, there was no muscular exertion, and water was taken 

 in abundance. 



Berard quoted 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 com- 

 plete deprivation of food is referred to in works on physiology. Berard 

 has also quoted from various authors instances of deprivation of food 

 for periods varying between four months and sixteen years ; but these 

 accounts have been discredited by physiologists. They occurred usually 

 in hysterical females ; and their consideration belongs to psychology 

 rather than to physiology. According to the observations of Chossat, 

 death from starvation occurs after a loss of four-tenths of the weight 

 of the body, the time of death, however, being very variable in different 

 classes of animals. 



Thirty to thirty-five days may be taken as the average duration of 

 life in dogs deprived entirely of food and water. It is important to bear 

 in mind this fact in connection with observations on the nutritive value 

 of different articles of food. 



