308 THE LAWS OF ORGANIC 



were interrupted by irregular pauses, with an 

 appearance of watching for some favourable op- 

 portunity for making the succeeding effort ; and 

 it seemed as if the action of inspiration were in 

 some manner to be guided by the tendency of 

 the vessel to pitch, with an uneasy motion. 



" The sickness occasioned by swinging is evi- 

 dently from the same cause as sea-sickness. 



" It is during the subsidence (of the vessel) 

 that the blood has a tendency to press with un- 

 usual force upon the brain."* 



CCCXL1V. Dr WOLL ASTON tried to induce 

 the same sensation by swinging ; and when this 

 was present, he endeavoured to remove it by 

 making deep inspirations. He says, " Although 

 the advantage was manifest, I must confess it did 

 not fully equal the expectations I had formed 

 from my experience at sea." The result of this 

 experiment is in accordance with the principles 

 proposed. It is the more frequent or irregular 

 inspirations that are the cause of the various symp- 

 toms. 



CCCXLV. There is a great difference between 

 an involuntary and a voluntary inspiration. In the 

 former the whole system is relaxed, or predis- 

 posed to increase the full effect ; in the latter, the 

 very attention or desire of the mind to enforce, 

 counteracts, in part, the consequences we antici- 

 pate. 



* Lend, Phil. Trans. 1810. 



