192 Mayow 



where the interior muscle a^ a^ will raise the lower 

 and more mobile rib, in contracting, as well as the 

 exterior muscle, 3, b. And here it is to be noted 

 that the ribs are so articulated with the spine that 

 when they are pulled by the said muscles they easily 

 ascend and are raised with rotation. 



Nay, the very position of the muscles makes this 

 plain, for if the interior muscle which is placed 

 between the two lowest ribs were to pull the upper 

 of the two downwards, all the ribs, since they are 

 firmly attached to each other, would necessarily be 

 drawn downwards at the same time, a thing which 

 that weak and membrane-like muscle cannot do. 

 How much more probable is it that the lower 

 ribs are all drawn upwards together by the internal 

 muscles between the upper ribs, for these are suffi- 

 ciently strong and broad, while the weaker muscles 

 between the lower ribs contribute merely to elevate 

 the lower ribs. These things will be more clearly 

 seen from Fig. 3, which shows the ribs and the 

 internal muscles. 



And this view is also supported by the oblique and 

 contrary position of the intercostal muscles. For 

 Nature seems to have inserted these muscles obliquely 

 in the ribs (although a direct insertion would have 

 suited better for moving them up or down) because 

 the intervals between the ribs are so small that if 

 these muscles had been inserted at right angles, they 

 would have been shorter than the nature of muscles 

 admits. Wherefore, that these muscles should have a 

 suitable length, they had to be inserted obliquely (as 

 they are) to the ribs. Yet as this oblique position is 

 less suitable for elevating the ribs. Nature, that most 

 wise engineer, has arranged the muscles with divers 

 aspects so that while they pull the ribs obfiquely with 



