viii TRANSLATOR'S INTRODUCTION. 



Cowper, Cheselden, and the Monros, laboured in Great Britain. 

 There were others, who made the structure and functions of 

 the nervous system their special study, — as Kriiger, Wrisberg, 

 Meckel, Lobstein, Walther, de Asche, &c. ; and thus, every 

 year, new facts and opinions were brought before the eclectic 

 intellect of Unzer, and, every year, he extended and perfected 

 his views. John Gottlieb Kriiger was a popular professor at 

 Halle, the native place and alma mater of Unzer, and he, 

 Haller, and Alexander Monro, appear to have had the greatest 

 influence on his mind; — Kriiger, by his doctrines as to the 

 involuntary nature of purely sensational movements ; HaUer, 

 by his inquiries into the nature of muscular action ; and 

 Monro, by his researches into the anatomy and physiology of 

 the nervous system. The doctrines of Haller as to the powers 

 and properties of the vis insita, he extended to the whole class 

 of purely automatic movements excited by mere impressions on 

 the nerves or nervous centres; the doctrines of Kriiger he 

 adapted to the preceding, and to that great class of excited 

 movements accompanied by, but not necessarily dependent on, 

 sensation : the ordinary metaphysical doctrines of the day, as 

 propounded by Baumgarten,^ were adapted to the current 

 physiology of the cerebrum ; and, finally, with all were incorpo- 

 rated the doctrine of Willis and Hoffmann, as to the nature and 

 seat of the conservative and curative powers of the organism. 



Thus, after twenty-five years had been devoted to his subject, 

 Unzer gave to the world his system of physiological meta- 

 physics. He lived and wrote far in anticipation of his age and 

 his contemporaries. That which he established hypothetically, 

 but logically, has since been demonstrated by dissection and 

 experiment; what he thought to be only perceptible to the 

 eye of reason, has been revealed to the eye of the histologist ; 

 what he discovered, intuitively but speculatively, has been duly 

 enrolled on the records of science as a proved thing. Yet, 

 after the lapse of eighty years, much that he advanced remains 

 to be duly appreciated; and the present age has still to 

 acknowledge, that his work is a model of psychological inquiry, 

 and a mine of suggestive ideas. 



» The translation from the Latin into German by Professor Meier, of Halle (1766), 

 is the edition of Baumgarten's * Metaphysics, to which Unzer refers in his work. 



