XVIII LIFE AND WORKS OF NICOLAUS STENO 



generis substantia, adeoqve nee certx substantias, ut ignis, calidi innati, 

 animx sedes, nee certi humovis, ut sangvinis, generator, nee spirituum 

 qvorundam, vitalium puta, productor. 



Steno's interest in the general anatomy and physiology of the 

 muscles visibly showed itself in a more extensive work on this subject, 

 which work he himself seems to have valued highly, but which is, 

 perhaps, now considered the weakest of his writings. The underlying 

 idea, however, is in itself highly praiseworthy. His point of view was 

 that all previous explanations as to the way in which the contraction 

 of the muscles took place were very improbable and, which was still 

 worse, very vague and obscure, and so he made it his aim to intro* 

 duce the exact mathematical method into the investigation and ex* 

 planation of the contraction of the muscles. Steno took a great interest 

 in mathematics, in which branch of science he possessed considerable 

 knowledge, and he was of the opinion that mathematics might be ap* 

 plied in physiology and become of as great importance there, as it 

 already was in other branches of science, e. g. astronomy. About the 

 same time the same idea had led Borelli to occupy himself with bring* 

 ing mathematics to bear upon the more mechanical side of the func* 

 tion of the muscles. Steno wanted to utilize the mathematical laws to 

 explain how the very contraction of the muscle took place. He 

 justly looked upon the muscular fibre as the elementary part, the 

 function of which, during the contraction, it was particularly important 

 to become acquainted with. When in spite of much diligence and the 

 most careful proofs he still did not arrive at a correct result, this 

 was due to the following two errors. Firstly his starting*point was 

 a wrong conception of the course of the muscular fibres. As has 

 been already mentioned he thought that every muscular fibre at either 

 end passed into a tendinous fibre, and he furthermore was of opinion 

 that the course of the muscular, as well as that of the tendinous fibre 

 were each of them rectilinear, forming an angle at the two places, 

 where the muscular fibre became a tendinous one, neither of which 

 suppositions have proved to agree with the actual facts. Secondly, 

 he did not pay attention to the fact that every separate muscular 

 fibre, when shortened by contraction, must needs become thicker, and 

 that this in its turn must act on the whole figure of the muscle du* 

 ring the contraction. 



Steno's interest in the special anatomy of the muscles displayed it* 

 sell some years afterwards in his thorough description of the muscles 

 ot an eagle, which he dissected during his stay in Copenhagen in 1673. 



Further we must mention the experiment, which still bears Steno's 

 name, and which consisted in his ligaturing the descending aorta of 

 a living animal, the consequence of which was a paralysis ofthe hind* 

 legs, which paralysis ceased when the ligature was removed. 



