iSz THE HISTORY OF BIOLOGY 



to his lack of interest in anatomy. Nor, indeed, did his contemporary age 

 realize the importance of this question; it was not until sixty years after 

 Stahl's death that Bichat, basing his results on anatomical studies along 

 many different lines of inquiry, established the vital part played by the 

 tissues in maintaining the functions of the body, but, as we shall see later 

 on, he had come from a school in France that adopted and developed Stahl's 

 ideas. 



Doctrine of the soul as cause of life-phenomena 

 The theory of Stahl's which aroused most interest in his time — that is, 

 which evoked most applause and most controversy — was his doctrine of 

 the soul as the cause of all life-phenomena, as their one supreme condition 

 and their final aim. This "animistic" conception of the structure and func- 

 tions of the body, according to which every manifestation of life, whether 

 it is a question of the absorption of food, the blood-circulation, the processes 

 of secretion and excretion, or simple movements from one place to another, 

 muscular activity and sensations, takes place exclusively for the sake of the 

 soul, is induced by it, controlled by it, and pursues its normal course thanks 

 to it — this theory, so utterly opposed to the contemporary mechanical con- 

 ception of life, was in reality the one main factor for Stahl, the very founda- 

 tion on which he built up his medical system. For Stahl aimed at creating 

 a new medical science, and his speculations in common biology were in- 

 tended merely to lay the foundations of that science. Naturally, the dis- 

 eases of the body are also caused by the soul; if it relaxes its control of the 

 body or any part thereof, there at once ensues general or local decomposition 

 of the inconstant chemical associations of which the body is made up, and 

 sickness or death results. And Stahl does not hesitate to follow up this theory 

 to its ultimate conclusions: if the soul desires to do so, it can naturally keep 

 the body whole, but, as it happens, the soul is wayward, inconstant, and 

 inconsiderate, and the body has to suffer for it. The soul of animals possesses 

 in this respect less freedom of action than the human soul, with the result 

 that animals are less often sick. One would suppose that in these circum- 

 stances any kind of medical treatment would be superfluous, since it has to 

 deal with the body, which is in any case powerless, but Stahl does not draw 

 this conclusion; like the homoeopaths of a later period, however, he pre- 

 scribes remedies having a mild action, with which he believes it possible to 

 help the soul in its functions to the improvement of the body; violent 

 remedies, such as quinine and opium, he deprecates. There is one con- 

 clusion that he draws from his system which does him honour — namely, 

 when he prescribes mild treatment in mental cases; otherwise the physicians 

 of his age, even the most humane, generally employed violent and sometimes 

 brutal methods in their attempt to drive out the mental disease from the 

 unfortunates who were thus afflicted. 



