PHYSIOLOGY. 23 



iilarum quas pro pure medico scopo, pro efficiente causa agnos- 

 cere sufficere poterat) sit in Homine ipsa Animc? he adds, 

 * Agnosco quod hac propositione, utpote non tarn ad medicam 

 quam physicam anthropologiam plane supersedere potuissem.'' 

 We shall show this more at large hereafter; but I say that 

 the opinion of Dr. Stahl is not only superfluous with regard to 

 physic, but it is somewhat incompatible with the study and 

 practice of it : for if we do not suppose that the causes acting 

 upon the human body produce their effects from a physical 

 necessity, we can neither judge of the effects of the causes of 

 disease, nor of the operation of remedies. To this purpose I 

 shall mention a passage from Dr. Gaubius. Where he enume- 

 rates the causes of sleep, (Institut. Pathol. 7^9.) he gives 

 some as depending upon the corporeal parts ; he adds a fourth 

 cause, but very properly with aforsan: that one cause of sleep 

 may be, that the soul is either tired or is too lazy, and therefore 

 animalibus organis relaxatis, lubens ab opere feriatur ; but 

 if we are to admit of the possibility of such causes, I refuse 

 that we can distinguish when the material part, or when the 

 capricious whim of the soul is the cause, and we are done with 

 studying physic, with attaching any importance to the causes 

 we have observed, or to the operation of remedies ; for all these 

 may be varied by things out of our reach. The Stahlians have 

 spoken of causes, and are willing to admit of such ; causes, how- 

 ever, must be physical and not arbitrary ; in short, whatever I 

 say in joining with Dr. Gaubius, with regard to the soul having 

 a power of beginning motion, yet in matters of physic we must 

 entirely abstract from it; and, therefore, whatever is in that, we 

 must still keep to the language of Whytt, Boerhaave, Haller, 

 and the greater part of the other writers upon the subject. It 

 is true, the language of Boerhaave and the others will 

 seem to be the same with the language of the materialists, 

 but a very little explanation will always shew the difference. 

 I, in using their language, will seem to talk as a materialist ; 

 and very unhappily some persons have understood me so. I 

 have however particularly guarded against this." 



XXXII. The phenomena of the nervous system occur 

 commonly in the following order. The impulse of external 

 bodies acts upon the sentient extremities of the nerves ; and 



