372 MANIPULATION. 



st&pped, but the circulation still continues, the animal can 

 then be very easily managed ; as soon as the body is opened, 

 the lungs, from being full of air, will protrude ; one of these 

 is to be taken and bent over on a piece of glass placed on the 

 stage of the microscope, and, viewed in the ordinary way, 

 the magnificent sight then disclosed will baffle all powers 

 of description. If the mesentery be required for the same 

 purpose, it may, Hke the lung, be spread upon a plate of glass 

 and examined in a similar manner. 



The circulation in the mammalia is to be seen, but not so 

 distinctly as in the reptiles, the parts generally selected being 

 the wing of a bat and the thin ear of a small mouse; for 

 this purpose the body of each animal must be firmly secured, 

 and in the case of the former the wing may be held down 

 by braces of cardboard ; the largest vessels will be found in 

 the neighbourhood of the bones of the wing, from which they 

 may be traced into the more transparent parts. The ear of 

 the mouse is more diflScult to manage; after securing the 

 body, one of the ears, slightly compressed by a brace, may 

 then be examined ; the circulation will be most clearly seen 

 near the edge, but at the best of times the management 

 of this active Httle animal will be found very troublesome. 

 LuckHy, however, anasthsetic agents have the same power 

 over these creatures as over the human subject, and the 

 administration of chloroform may be adopted with the greatest 

 success to keep both the bat and the mouse perfectly quiet 

 without stopping the circulation of their blood. 



