4 THE LAWS OF ORGANIC 



from being regular either in velocity or quantity 

 in any given point, even for a series of hours, 

 Many experiments were made on the lower ani- 

 mals to elucidate a few of the above observations, 

 but, by attending to these, it was almost impossi- 

 ble to appreciate the precise influence of inspira- 

 tion and expiration upon the system. Except by 

 direct experiment this could be ascertained only 

 by repeated observations on man himself, when 

 excited or depressed by the emotions of the mind, 

 as it is then that these powerful states exhibit 

 each of these acts in its extreme developement 

 and its subsequent results. 



VII. The experiments of Dr BARRY* fully 

 prove that the blood during inspiration circu- 

 lates with freedom through the lungs, but that 

 during expiration the contrary is the case. 



Dr BOSTOCK, in alluding to these experi- 

 ments, observes, " The obvious objection to such 

 experiments in the abstract is, that they apply 

 to what occurs in extraordinary states of the res- 

 piration rather than to its ordinary action, and 

 that, in the healthy condition of the system, the 

 different states of the thorax cannot be perceived 

 to affect the pulse." With these remarks of this 

 distinguished physiologist I cannot agree. 



VIII. In the first place, if, in a violent in spira- 



* Vide Experimental Researches on the Influence of 

 Atmospheric Pressure upon the Circulation and Absorption ; 

 8vo, London, 1826. 



