COMPARISON OF COLD AND WARM-BLOODED ANIMALS. 



71 



A careful consideration of these tables, in connection with previous researclies, 

 will tend to support the following conclusions : — 



1. The intellect, temperature, nervous and muscular forces, and organic develop- 

 ment of animals, are in proportion to the rapidity of the changes of the elements. 



In warm-blooded animals, which are endowed with intellect of a high order, and 

 possess great nervous and muscular force, and correspondingly developed organs, the 

 changes in their elements are incessant. When starved, they lose weight rapidly. 



In cold-blooded animals, the temperature of which is often below that of the sur- 

 rounding medium, and whose nervous system and intellect are feebly developed, 

 the changes in their elements are correspondingly slow. 



The Cur-dog lost, in six days and fourteen hours, one-third of its original weight, 

 whilst the Chelonians lived from thirty to sixty days without losing more than 

 from one-fourth to one-thirteenth of their original weight. The loss in the former 

 Avas from six to fifteen times more rapid than in the latter. 



2. The loss of weight at the time of death was very nearly equal in warm 

 and cold-blooded animals. The maintenance of the short, vigorous life of the 

 former, required as large a supply of organic and inorganic materials as the pro- 

 longed and sluggish existence of the latter. What the warm-blooded animal 

 gained in intensity and power, it lost in duration. 



3. The length of life of an animal during starvation and thirst, is proportional 

 to the rapidity of the changes of its elements, and, as a necessary consequence, 

 stands in direct relation to its temperature, intellect, and organic development. 



The Cur-dog wasted more rapidly, lived more energetically, and died in a corre- 

 spondingly shorter time, than the cold blooded Chelonians. 



Amongst cold-blooded animals, the Terrapins which were most active in their 

 movements, and whose nervous system was the most excited, lived during a time 

 corresponding with their increased nervous and muscular exertions. 



The female Terrapins, whose ovaries and oviducts were filled with hard and soft 

 eggs, lost from arVs^^ 3"irT3^^^ of their weight hourly, and died in the course of 

 twenty-five or thirty-five days; while the females which had deposited their eggs, 

 and the males, which were free from these anxieties, wasted only one-half as much 

 per hour — ^^Jg gth to ^Q^jth of their whole weight — and lived twice the length of 

 time — from fifty to seventy days. 



We may infer from these facts, as far as they extend, that the acts of life are 

 carried on upon the same general plan, no matter what be the physical or vital 

 constitution of an animal. 



4. In cold-blooded animals, the organs, tissues, and apparatus are far more 

 independent of the blood than in warm-blooded ones. 



This fiict will explain the phenomena of the prolonged contraction of the heart 

 and muscles, and the action of the nervous system, and the continuance of life, for 

 a great length of time after the almost complete removal of the blood. These 

 functions are attended with so little waste, and consequent demand for a fresh 

 supply of nutriment, that a very small amount of the circulatory fluid will suffice 

 to keep them in action for a great length of time. 



In Avarm-blooded animals, on the other hand, the maintenance of the nervous 



