166 THE LAWS OF ORGANIC 



the excited activity of its functions,but to the ob- 

 servance of those intimate relations subsisting be- 

 tween the powers which add and those which sub- 

 tract. Whenever the former predominate over 

 the latter, life then displays its exuberance, the 

 plant throws out its leaves or expands its flowers, 

 and the energy of the animal frame is concen- 

 trated to strengthen old or develope new func- 

 tions, or to excite disease ; and when the latter 

 become superior to the former, the plant droops, 

 and the animal decays. But if these powers are 

 equally diminished, as vegetation is in winter, or 

 as happens to animals in a state of torpidity, it is 

 almost impossible to prescribe boundaries to their 

 duration. 



CLXXXIV. Many theories have been pro- 

 posed to explain the cause of torpidity. MAN- 

 GILI imagined that the veins are larger, in pro_ 

 portion to the arteries, in hybernating than in 

 other animals. " He supposes, in consequence 

 of this arrangement, there is only as much 

 blood transmitted to the brain during sum- 

 mer as is necessary to excite that organ to 

 action. In winter, when the circulation is 

 slow, the small quantity of blood transmitted 

 to the brain is inadequate to produce the ef- 

 fect."* PALLAS observed the thymous gland 

 and two small glandular bodies under the throat 



* The Philosophy of Zoology, by JOHN FLEMING, D. D, 

 Vol. II, p. 61. 



