CIRCULATION OF THE BLOOD. 125 



a portion of the dried intestine of a dog or wolf, or any other 

 animal, such as we see hung up in the druggists' shops, be taken 

 and filled with water, and then secured at both ends like a 

 sausage : by tapping with the finger at one extremity, you 

 will immediately feel a pulse and vibration in any other part 

 to which you apply the fingers, as you do when you feel the 

 pulse at the wrist. In this way, indeed, and also by means 

 of a distended vein, you may accurately either in the dead or 

 living body, imitate and show every variety of the pulse, 

 whether as to force, frequency, volume, rhythm, &c. Just as in 

 a long bladder full of fluid, or in an oblong drum, every stroke 

 upon one end is immediately felt at the other ; so also in a 

 dropsy of the belly and in abscesses under the skin, we are 

 accustomed to distinguish between collections of fluid and of 

 air, between anasarca and tympanites in particular. If a 

 slap or push given on one side is clearly felt by a hand placed 

 on the other side, we judge the case to be tympanites [?] ; not, as 

 falsely asserted, because we hear a sound like that of a drum, and 

 this produced by flatus, which never happens [?] ; but because, 

 as in a drum, every the slightest tap passes through and pro- 

 duces a certain vibration on the opposite side; for it indicates 

 that there is a serous and ichorous substance present, of such 

 a consistency as urine, and not any sluggish or viscid matter 

 as in anasarca, which when struck retains the impress of the 

 blow or pressure, and does not transmit the impulse. 



Having brought forward this experiment I may observe, that 

 a most formidable objection to the circulation of the blood rises 

 out of it, which, however, has neither been observed nor adduced 

 by any one who has written against me. When we see by the 

 experiment just described, that the systole and diastole of the 

 pulse can be accurately imitated without any escape of fluid, it 

 is obvious that the same thing may take place in the arteries 

 from the stroke of the heart, without the necessity for a circu- 

 lation, but like Euripus, with a mere motion of the blood alter- 

 nately backwards and forwards. But we have already satis- 

 factorily replied to this difficulty; and now we venture to say 

 that the thing could not be so in the arteries of a living animal ; 

 to be assured of this it is enough to see that the right auricle 

 is incessantly injecting the right ventricle of the heart with 

 blood, the return of which is effectually prevented by the 



