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matter of importance, however, is his description of what is perhaps the 

 first plethysmograph experiment. The arm of a living person was 

 placed in a cylindrical glass vessel with one end drawn out like a funnel 

 and then the whole filled with water. When the person contracted 

 his arm muscles the level of the water in the narrow tube fell ; 

 therefore, it was plain that during contraction a muscle was not 

 inflated by any spirit or juice as supposed by Borelli. The variation 

 in volume we now know was due to the effect of contraction on the 

 blood-stream. We come again upon the same idea in Swammerdam's 

 work. " The invention of this experiment is, however, by some 

 attributed, upon the authority of the register of the Royal Society, to 

 Dr. Goddard " (Aikin). 



Glisson was also the founder of the doctrine of " irritability," a 

 doctrine again taken up by Haller. Glisson used the word in its 

 widest sense to indicate the power of parts to respond to various 

 forms of stimuli to which reference is made elsewhere. 



NICOLAUS STENSEN. 



1638-1686 (at. 48). 



NIELS STENSEN is one of the most picturesque, pathetic, and 

 withal brilliant of the apostles of physiology in the seventeenth 

 century — Anatomist,Physiologist, Physician, Geologist, Priest, 

 and Bishop. In his short span of less than fifty years he left an enduring 

 mark of his genius, both on physiology and geology. He is perhaps 

 better known by his Latin name of STENO. In 1656 he attended the 

 University of his native town, where it was then the custom for a 

 student to attach himself to some particular Professor, and Stensen 

 chose Thomas Bartholinus. Simon Paulli, the precursor of Bartholin 

 in the Chair of Anatomy, was also one of his teachers. It was 

 customary for Danish students, after passing three years or so at 

 their own University, to proceed to other Universities. Thus, we find 

 Stensen in Amsterdam, three years later, in the house of Gerh. Blasius, 

 a former pupil of T. Bartholinus. 



Scarcely had Stensen, in 1661, begun to dissect, when he dis- 

 covered the duct of the parotid gland, which bears his name, ductus 

 Stenonianus. This discovery led to a dispute with Blasius, and 

 Stensen went to Leyden, where, on the 6th and 9th of July, with 

 Van Home as president, he gave a brilliant Disputation on his 

 discovery of the glands with ducts. Later, he investigated the glands 

 connected with the eyeball — De Glandidis Oculorum. (Lugd. Batav. 



