INFLUENCE OF TEMPERATURE. 421 



cold-blooded animal. The lungs are relatively very small, and 

 it is some time before they fully assume their function. The 

 muscular movements are hardly more than is necessary to take 

 the small amount of nourishment consumed at that period, and 

 nearly all of the time is passed in sleep. There is also very 

 little power of resistance to low temperature. Though accu- 

 rate researches regarding the comparative quantities of oxy- 

 gen in the venous and arterial blood of the foetus are wanting, 

 it has been frequently observed that the difference in color is 

 not as marked as it is after pulmonary respiration becomes 

 established. The direct researches of W. F. Edwards have 

 shown that the absolute consumption of oxygen by very 

 young animals is very small ; l and the observations of Legal- 

 lois on rabbits, made every five days during the first month 

 of existence, show a rapidly increasing demand for this prin- 

 ciple with age. 2 



Regnault and Keiset have shown that the consumption 

 of oxygen is greater in lean than in very fat animals, pro- 

 vided they be in perfect health. They have also shown that 

 the consumption is much greater in carnivorous than in 

 herbivorous animals; and in animals of different sizes, is 

 relatively very much greater in those which are very small. 

 In very small birds, such as the sparrow, the proportional 

 quantity of oxygen absorbed was ten times greater than in 

 the fowl. 3 



In sleep, the quantity of oxygen consumed is considerably 



1 De V Influence des Ay ens Physiques sur la Vie, Paris, 1824, p. 178 et seq. 



2 Loc. cit. In his experiments on rabbits, Legallois found that immmediately 

 after birth they would live for fifteen minutes deprived of air. " In asphyxiating 

 rabbits of different ages, for example, every five days, from the moment of birth 

 to the age of one month, it was constantly observed that the duration of sensa- 

 tion, of voluntary motion, in a word, the signs of life, always diminished in pro- 

 portion as the animals advanced in age. Thus, in a rabbit newly born, sensation 

 and voluntary movements were not extinct until the end of about fifteen minutes 

 of asphyxia, while they were extinct in less than two minutes in a rabbit of the 

 age of thirty days." Pp. 57, 58. 



8 Loc. cit. 



