148 PHILOSOPHICAL TRANSACTIONS. [aNNO I674. 



for the foetus to breathe in the open air, there being now nothing to compensate 

 the defect of that respiration. 



Let us pass to the last, which is of muscular motion and animal spirits. It is 

 undoubted, that the motion of animals is made by the contraction of the mus- 

 cles ; but it is controverted in what manner that contraction is made. The most 

 received opinion is, that the fibres of the muscles are inflated by some elastic 

 matter, swelling them as to their breadth, but contracting them as to their 

 length ; though the learned Steno in his Myology thinks it needless to take in 

 a springy matter for the contraction of the muscles ; forasmuch as he judges it 

 may be effected by the sole change of their figure. Concerning which our 

 author considers that it appears not ; 1 . How that motion, requisite to make a 

 change in the figure, can be produced without the accession of some new 

 matter, 2. How it comes to pass, if no new matter enters the muscle, that in 

 its contraction it is so sensibly hard and tense. And whereas anatomists have 

 hitherto taught, that the carneous fibres chiefly make the contraction in mus- 

 cles, our author thinks it more probable, that the fibrillae, transversely inserted 

 into the greater fibres, perform the chief part in that contraction, by reason as 

 well of their position as their size and number. And as to the cause of this 

 contraction in these fibrillae, he thinks, that besides the animal spirits, there are 

 also required to this motion some of the salino-sulphureous parts of the blood ; 

 and that those animal spirits, that contribute to the animal motion, consist of 

 those nitro-aerial parts, which he asserts to be transmitted into the blood by 

 inspiration. And both these parts he judges necessary to this muscular motion, 

 because he understands not how that animal motion can be performed without 

 different particles mixed together and briskly moved; in regard that, in his opi- 

 nion, it cannot be effected by springiness and weight, which do the work in 

 automatons, since their impetus will soon cease: whence he concludes, that 

 the muscular contraction is performed by the effervescence of the salino-sulphu- 

 reous and nitro-aerial particles. 



II. Anatome Corporis Humani, conscripta ab Isbrando de Diemerbroeck,* 

 Med. et Anatomes Professore, Ultrajecti, l(371,in4to. 



* Isbrand van Diemerbroeck was a celebrated Dutch physician of the I7th century. He practised 

 for several years at Nimeguen, and wrote an account of the dreadful plague, which raged there in 

 1635, 1636, and 1637. He afterwards removed to Utrecht, where he was appointed to the profes- 

 sorship of physic. He died in l674, aged 65. Besides the abovementioned anatomical work, several 

 other treatises were written by this author j viz. De Variolis et Morbillis ; Obsen'at. et Curationes 

 Medicaej Disputationes Practicae, &c.; but his principal work is that De Peste, first published in l6i6, 

 4to. and reprinted^ some years after his death, with his otlier writings, under the title of Opera Omnia, 

 Utrecht, l685 folio. During the raging of the abovementioned pestilence, Diemerbroeck attended 



