72 Mayow 



/ Let a moistened bladder be stretched over the cir- 

 cular orifice of any vessel and tied to it just as the skin 

 of a drum is stretched ; then let a small bell-jar in which 

 a little animal, say a mouse, has been put, be accurately 

 applied to the said bladder by placing a weight upon 

 the jar lest the animal inside should upset it (as is 

 shown in Plate V., Fig. 2). When things have been 

 arranged in this manner it will in a short time be seen 

 that the jar is firmly fixed to the bladder ; and the 

 bladder also, at the place where it lies under the jar, is 

 forced upwards into the cavity of the glass just as if 

 the jar had been applied with a flame enclosed in it. 

 And this will take place while the animal is still 

 breathing. Nay, if the jar be grasped by the hand and 

 raised, the bladder, along with the vessel, will still 

 adhere firmly to it unless the vessel is very heavy. 

 And indeed a little animal placed in a cupping-glass 

 which is to be fixed to the skin can supply to a small 

 extent the place of the flame. And from this it is 

 clear that the elastic power of the air enclosed in the 

 aforesaid jar has been diminished by the breathing of 

 the animal, so that it is no longer able to resist the 



A pressure of the surrounding air. 



But in order that this matter may be better under- 

 stood, let me submit yet another experiment to the 

 same effect — an experiment moreover from which it 

 will be easy to perceive in what proportion the air is 

 diminished as to its volume when deprived of vital 

 particles by the breathing of the animal. Thus, let a 

 small animal placed on a suitable support be enclosed 

 in an inverted glass, or better, let the animal be put 

 into a suitable cage and suspended in a glass jar just as 

 the vessel is suspended in Plate V., Fig. 4. Then let 

 the inverted glass be sunk a little into the water so 

 that the water enclosed in the glass may stand at the 



