LECTURE I. 29 



no peculiar arrangement of arteries. Though 

 we cannot excite any sudden contraction 

 of that bag, yet we know that it can gra- 

 dually reduce itself into a very small com- 

 pass. The skin has every where this slow 

 but permanently acting, and gradually re- 

 laxing irritability, the effects of which are 

 most evident in lax and pendulous por- 

 tions of it. Accordingly we sometimes ob- 

 serve the scrotum and prepuce condensed 

 into a suprizingly small and very compact 

 mass. 



Thus have we even in the human body 

 evidences of irritability acting in various 

 modes, whilst we can equally perceive that 

 in tardigrade animals some of their mus- 

 cles act with celerity. In the lori, of whose 

 habits Vosmaer has given so interesting an 

 account, and which manifested no signs of 

 alacrity, save in eating the food that it liked, 

 no stimulation nor injury could induce it 

 to mend its pace, but it showed its resent- 

 ment of the attempt to make it perform 

 impossibihties, by suddenly snapping at 

 the stick or instrument with which it was 



