TRANSLATOR'S INTRODUCTION. vii 



of that principle were alone to be investigated. According to 

 his viewSj the involuntary, instinctive, and habitual acts of the 

 organism, are produced unconsciously by the soul ; being 

 adapted, they result ratione, or Xoyw, but not ratiocinioy or 

 Xoyiafxw. Hoffmann, on the contrary, seems to have been 

 eclectic, and to have constructed his system by modifying 

 those of Sylvius, Willis, Wedel, and Stahl. He recognises a 

 sensational soul, or anima sensitivay as distinct from the rational 

 soul ; and an etherial fluid, diffused throughout nature, is the 

 means by which this soul acts on the body. The blood receives 

 this ether from the atmosphere ; it is secreted from the blood 

 by the brain ; and, being transmitted thence along the nerves, 

 the anima sensitiva is enabled thereby to produce all the in- 

 stinctive and involuntary acts displayed by animal organisms. 

 The conservative and remedial powers manifested by the latter, 

 which Stahl attributed to the soul, Hoffmann considered to be 

 a law of life, seated in the general organisation, as Willis did 

 before him. He distinguished the nervous tissue from the 

 mus(5ular, and attributed the motive power of the former to a 

 vis nerve a, of the latter to a vis insita. 



Professor Juncker, the disciple and successor, at Halle, of 

 Stahl, and to whom Unzer attached himself, was the contem- 

 porary of Hoffmann, and therefore, in some respects, the 

 antagonist. Unzer seems to have attached himself to his 

 master with youthful enthusiasm, and to have defended the 

 Stahlian doctrines, at the outset of his literary career, rather 

 from feeling than conviction. Perhaps he was influenced by 

 the doctrines of Hoffmann unconsciously to himself; — it is 

 certain that, imbued with the same spirit of eclecticism, he 

 quickly abandoned the Stahlian system and method of phi- 

 losophising, to investigate the phenomena of life and mind by 

 anatomical and physiological researches. During the time that 

 he was a student, and subsequently, general and histological 

 anatomy and experimental physiology were assiduously culti- 

 vated, and every year some interesting experiment or discovery 

 was made. It was then, or a few years previously, that 

 Lancisi, Valsalva, Pacchioni, Baglivi, Santorini, Morgagni, 

 and Spallanzani flourished in Italy, — Winslow and Vicq d'Azyr 

 in France, — Albinus in Holland, — and Lieberkiihn, Haller, 

 (his distinguished pupils,) and Sommerring in Germany ; while 



