MEMOIR OP BARON HALLER, 3J 



the very structure of the heart itself The nature of 

 the thing obliged me to differ in opinion from my 

 preceptor. Three years afterwards I published the 

 following doctrine, viz. That all animal fibres when 

 they were irritated contracted themselves; that this 

 character distinguished them from those of vegetables, 

 and that perpetual irritation alone was the cause of 

 the continuance of motion in the vital organs, while 

 the animal organs ceased to act. In the abridgement 

 of my Physiology I have positively ascribed the 

 motion of the heart to the force of a stimulus; and 

 in the second edition, I have been more explicit on 

 the irritability of muscular fibre, asserting that it 

 was independent of the nerves, and of every other 

 known property. If any person denies the truth 

 of this assertion, I shall be glad to learn from him 

 upon what property this motion depends. Since that 

 time, numerous experiments have convinced me of 

 the truth of the doctrine above advanced.** 



We shall in this place introduce a very succinct ac- 

 count of Haller's separate treatise on this interesting 

 point. He divides all the parts of animals into those 

 which are susceptible of irritability and sensibility, 

 and those which are not. He designates irritable 

 those parts which become shorter upon the applica- 

 tion of a stimulus, and sensible, those which on being 

 touched transmit the impression to the sentient 

 being ; and, on the contrary, those are denominated 

 insensible in which the most violent injuries occa- 

 sion no pain or convulsive movement. These defi- 

 nitions are followed by a minute examination of the 



