152 Circulation of the Blood 



senses, no more certain demonstration or means of 

 gaining faith can be adduced than examination by the 

 senses, than ocular inspection. 



There is one remarkable experiment which I would 

 have every one try who is anxious for truth, and by 

 which it is clearly shown that the arterial pulse is owing 

 to the impulse of the blood. Let 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 produces 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 cir- 



