XVII] BLOOD VESSELS. CIRCULATION 141 



the left side, the cut beginning a little below the fore leg and 

 extending for 1 to 1^ cm. The pylorus and the part of the 

 intestine below it are pinned out. The circulation in the 

 mesentery is also seen, but less satisfactorily than in the lower 

 loop of the intestine. The same cut allows the lung to be pulled 

 out, and the circulation in it observed. 



11. Preservation of inflamed mesentery. When the circulation 

 has been observed, cover up with a funnel lined with wet 

 blotting-paper till next day. Remove the lower part of the 

 intestine with its mesentery, and wash with salt solution. Fix 

 the mesentery in alcohol, cut it into two parts, stain one with 

 Ehrlich-Biondi fluid, and the other with hsematoxylin and 

 eosin. Mount in balsam. Note the numerous leucocytes with 

 irregularly shaped or fragmented nuclei outside the capillary 

 walls. A large number of coarsely granular oxyphil cells are 

 usually seen (cp. Less. x. 10). 



DEMONSTRATIONS. 



1. Aorta of large animal stained with orcein to 

 show the elastic tissue, longitudinal section. 



2. Transverse section stained with orcein of vessels 

 of 1 to show the elastic tissue. 



3. Longitudinal section of vein including valve. 



4. Circulation in the lung of the frog or toad 

 (cp. p. 191). 



