IN MEDICAL SCIENCE. 15 



being converted into unchangeable heat, so that the 

 universe will come to a stand-still at last, all force pass- 

 ing into heat, and all heat into a state of equilibrium. 



The doctrines of the convertibility or specific equiv- 

 alence of the various forms of force, and of its conser- 

 vation, which is its logical consequence, are very gen- 

 erally accepted, as I beheve, at the present time, 

 among physicists. We are naturally led to the ques* 

 tion. What is the nature of force ? The three illus- 

 trious philosophers just referred to agree in attributing 

 the general movements of the universe to the imme- 

 diate Divine action.* The doctrine of " pre-established 

 harmony '^ was an especial contrivance of Leibnitz to 

 remove the Creator from unworthy association with 

 the less divine acts of living beings. Obsolete as this 

 expression sounds to our ears, the phrase laws of the 

 universe^ which we use .so contantly with a wider ap- 

 plication, appears to me essentially identical with it. 



Force does not admit of explanation, nor of proper 



* " Et generalera quod attinet, manifestnm mihi videtur illam [causam] 

 non aliam esse, quam Deum ipsum, qui materiam simul cum motu et 

 quiete in principio creavit, jamque per solum suum concursum ordinarium, 

 tantundem motus et quietis in ea tota quantum tunc posuit conservat : . . . . 

 eodem plane modo, eademque ratione qua prius creavit, eum etiam tantun- 

 dem motus in ipsa semper conservare." — Des Cartes, Princ. Phil., P. 11. 

 § XXXVI. 



" Concursus Dei, actioni creaturse necessarius." — Leibnitz, Op., Tom. 

 VI. p. 174. 



" In ipso continentur et moventur universa, sed absque mutua passione. 

 Deus nihil patitur ex corporum motibus : ilia nullam sentiunt resistentiam 

 ex omniprassentia Dei." — Newton, Principia, Lib. III. Schol. Gen. 



