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I CANNOT omit mention of that singularly gifted observer, 

 and indefatigable naturalist, JAN SWAMMERDAM, who was 

 born at Amsterdam in 1637. He travelled, like all the great 

 Dutchmen of his time, to Italy and Paris. In Paris he stayed with 

 Stensen in the house of Thevenot. He took his M.D. at Leyden in 

 1665. Unfortunately for science he was afflicted with an incurable 

 melancholy, and died in 1680 set. 48. As already stated, he was the 

 first to see the red blood corpuscles of the frog, and his great work, 

 Biblia Naturae, was published in 1737-38, long after his death, by his 

 compatriot Boerhaave. The following illustration, taken from the 

 Biblia Natures, shows how Swammerdam studied some problems 

 of muscular action. Most interesting of all are his experiments on 



»FT 



JAN SWAMMERDAM'S FIGURES FROM "BIBLIA NATURE," REGARDING CONTRACTION OF 

 MUSCLE V., VI., VOLUME OF MUSCLE VIII., IX., AND OF HEART VII. 



the volume of the heart. He placed the heart in a glass syringe 

 with its nozzle drawn out to a fine tube. In the latter he placed a 

 drop of water and watched it rise and fall with every diastole and 

 systole of the heart. (Fig. VII.) He had anticipated by two centuries 

 the plethysmographic researches of Blasius, Fick, Mosso, Marey, and 

 others. In his experiments on muscle also, in Fig. V., when the 

 muscle contracted the two hands — in Fig. VI. the two pins were 

 drawn together — obviously he was at the very edge of a great 

 discovery. It only wanted a recording surface, and the graphic method 

 would have been invented. Figs. VIII. and IX. show his method of 

 studying any change of volume of a muscle during contraction. Here 

 a muscle is used instead of the arm in the experiment described 

 by Glisson. 



His Tractatus ele Respiratione (1667) is of special interest. He 

 imitated the movements of the chest wall by means of a pair of bellows. 

 He placed an animal in water as shown in the illustration — the 

 trachea connected with a tube with its orifice above the water — and 

 observed the rise and fall of the water in the vessel with the move- 



