XX LIFE AND WORKS OF NICOLAUS STENO 



sheer fancy. Any intimate knowledge of the more minute structure of 

 the brain was, of course, quite out of the question ; it was hardly known 

 that the substance of the brain at some places was made up of fibres, 

 and there was an absolute ignorance of its being so everywhere. As 

 to the different theories concerning its function, they were, really, 

 only at variance as to the distribution of the mental faculties in the 

 ventricles of the brain, and as to the part played by the animal spi* 

 rits. Descartes and Willis were — each in his own way, and only partly 

 — exceptions to this. That Steno did not estimate Descartes very 

 highly as an anatomist has already been mentioned, nor was he 

 greatly attracted by Willis. A sane observer like Steno could not help 

 noticing that, although much in Willis was founded on correct ob* 

 servations, much, on the other hand, rested on pretty similes and ana* 

 logisms, which were to be taken as proofs. Characteristic of Steno s 

 view of the physiology of the brain are the following words, with 

 which his Discourse opens: Au lieu de vous promettre de contenter 

 vostve curiosite, touchant I'Anatomie du Cexveau; ie vous fais icy une 

 confession sincere & publique, que ie n'y connois rien. He then proceeds 

 to demonstrate that all those self*relying men, who wrote on the brain, 

 knew as little about the matter as he, or rather less, and that all the 

 ideas, which they reckoned with, were only phantoms of their own 

 imagination. Even the very animal spirits, the existence of which at 

 that time was generally acknowledged, he mentions in the following 

 way : On voit encore moins de certitude, sur le sujet des esprits animaux. 

 Est=ce le sang? seroit=ce vne substance particuliere separee du chyle dans 

 les glandes du mesentere? les serositez n'en seroienUelles points les sources ? 

 II y en a qui les comparent a V esprit de vin, &■ Von peut douter si ce ne 

 seroit point la matiere mesme de la lumiere. Steno, however, is not con* 

 tent with pulling down the old building, he also gives advice, and very 

 good advice indeed, as to the way in which a new building is to be 

 erected. He speaks of the best ways of dissecting the brain; he de* 

 scribes, how the skull is to be opened, the best means of acquiring 

 trustworthy figures of the brain c\c. cxc. Of far greater importance, 

 however, is his assertion that first of all an effort must be made 

 to determine the course of the fibres in the brain, with which its 

 function to all probability is closely connected. Moreover he says 

 that valuable information might be obtained by comparing the brains 

 of animals, from the lower to the higher, as well as by comparing dif* 

 ferent stages of the development of the brain in the same animal, from 

 the fetus to the adult individual. Furthermore he refers to all the in* 

 formation to be had from the pathological anatomy of the brain; and 

 finally he recommends experiments on living animals, the brain of 

 which were to be examined, while drugs or poisons were either ad* 

 ministered in the ordinary way, or applied direct to the brain. 



