CHAP. IX.] THE CONTRACTILE TISSUES. 411 



sity of Edinburgh, whose criticism of Haller displays the greatest 

 ingenuity and address. This acute observer was not a disciple of Stahl; 

 indeed his doctrine was disclaimed by the purer Stahlists ; but it forms 

 a link between the teaching of Stahl and the doctrine of vital force 

 of the next generation. According to him all parts of the body are 

 pervaded by a Sentient Principle which is affected more or less acutely 

 by stimuli or irritants; and the motions which invariably follow 

 irritation and are always in proportion to the strength of it, are the 

 endeavour of the pervading principle to remove the part from the 

 source of irritation ; it acts upon the muscles through their nerves, 

 but in a manner altogether obscure. Whytt's sentient principle is 

 the soul of the Stahlists shorn of its rationality and spontaneity, and 

 bound by an original decree to the task of responding by movements 

 to every stimulus impressed upon the body. This principle remains 

 for a time in parts amputated from the body ; hence such parts are 

 capable of contractions when touched. It is the merit of Whytt to 

 have insisted upon tha importance of the stimulus in all involuntary 

 actions, and the invariableness of the motions excited by it. 



The experiments of Haller dealt a fatal blow to 

 Jolm Stahlism and the like. Already in the writings of 



Whytt we see this doctrine subsiding into the simpler 

 one of vital force, as it is implicitly adopted, for instance, in the pages 

 of John Hunter. Hunter 1 was content to classify muscular motion as 

 one of the forms of the movement of matter; of which the attraction 

 of masses owing to gravitation was another form and the elective 

 attraction of chemical substances was a third. He thought that it 

 most probably arose from construction : but it was a principle in action 

 very different from the attractions in common matter, and equally 

 unintelligible with gravity and chemical attraction. In short, the 

 current view of the cause of muscular motion was that it was original, 

 a vis insita, a vital power peculiar to living tissue during its life. 



Fothergiii, It was not long, however, before the doctrine of 



and Girtan- vital force began to be expanded. The re-discovery of 

 oxygen had quickened philosophical speculation, and 

 seemed to have placed in the hands of physicians a remedy of the 

 greatest promise. One of the first methods of treatment to be bene- 

 fited by the new chemical discoveries was the art of restoring sus- 

 pended animation. Inflation of the lungs was empirically known to 

 be extremely useful in such cases ; but it was Dr. A. Fothergill 2 who 

 first suggested an explanation of its value which, if not wholly true, 

 was true in the greater part. "In all cases of suspended animation 

 the grand intention ought to be, to excite the latent principle of 

 irritability on which the motion of the vital organs immediately 

 depends." And how, asks he, can this be better done than by 



1 Croonian Lectiire, 1781. Works, Ed. by Palmer, Vol. iv. p. 255. 

 ' 2 A. Fothergill, Hints for improving the art of restoring Suspended Animation, 1782, 

 pp. 15, 17, 18. 



