vn] of the Seventeenth Century. 193 



clear by Malpighi (seven years before he was writing), is admir- 

 ably fitted by its vesicles and tubes for such a purpose. He 

 illustrates his meaning by the well-known experiment of a 

 collapsed bladder expanding in a closed vessel as the air is 

 exhausted ; and makes a quaint model of the chest and lungs 

 by means of a bladder inserted in the cavity of a pair of 

 bellows so that the mouth of the bladder is continuous with 

 the nozzle of the bellows. When the bellows are expanded air 

 rushes into the bladder and fills it, when the bellows are 

 brought down the air is driven out again from the bladder. 



Asking the question how the chest is enlarged during 

 inspiration, he answers by the raising of the ribs and the 

 descent of the diaphragm ; the ribs are raised by the intercostal 

 muscles, both external and internal ; here he takes a side in a 

 controversy which nearly a century later became acute between 

 Haller and Hamberger, and has from time to time risen up 

 again ever since. The diaphragm descends by virtue of its 

 own contraction. 'Expiration he argues is in ordinary breathing 

 the mere passive result of relaxation, the ribs falling back into 

 their place and the contents of the abdomen pushing up the 

 diaphragm. And he enters into several minor details, such for 

 instance as the nature of the articulation of the ribs to the 

 spine, by which their movements are facilitated. The whole 

 account, as I have just said, might almost have been written 

 at the present day. 



He then proceeds to the larger question, What is the use of 

 breathing ? What effect is produced by breathing ? 



He ridicules the old and as yet still common view that 

 breathing serves for cooling the heart. The blood and its 

 fermentations he says seem to need heat rather than cold. 

 And violent exercise, even one so brief that the blood has 

 not time to get overheated, is followed by a much more 

 intense respiration than is the highest fever. 



He rejects the opinion which he affirms to be even more 

 common that breathing is to facilitate the passage of the blood 

 from the right to the left side of the heart. It is absurd, he 

 says, to suppose that such an elaborate mechanism is needed for 

 a mere transit. And indeed that the movements of breathing are 

 p. l. 13 



