2i 4 ZOOTOMY. 



distal barbules of any given barb overlap and cross at an angle the 

 proximal barbules of the barb next in advance. 



147. The booklets, minute curved processes on the distal barbules, 

 by means of which ihe latter are hooked on to the proximal barbules of 

 the next succeeding barb : the proximal barbules themselves are devoid 

 of booklets. 



XIX. Pluck out a filoplume and examine it in the same way : 

 note : 



148. The delicate stem, showing no distinction between calamus 

 and rachis. 



149. The rudimentary vane, consisting of a few barbs with simple 

 disunited barbules. 



XX. In the plucked bird, thrust a blowpipe into the 

 mouth and loop a string round the base of the 

 beak immediately behind the cere, tightening it 

 just enough to hold the blowpipe in place and 

 prevent the escape of air : inflate until the neck 

 and abdomen are greatly swelled owing to the 

 distension of the crop ( 150) and the air-sacs 

 ( 159) : withdraw the blowpipe, at the same time 

 tightening the ligature : then knot the latter to 

 prevent its loosening. 



By this method both crop and air-sacs are inflated 

 simultaneously without injury to any of the 

 structures to be afterwards examined : if in the 

 course of dissection one or other should collapse 

 which is certain to happen sooner or later cut 

 across the trachea (151) and inflate the crop from 

 its anterior and the air-sacs from its posterior end, 

 ligaturing as before. 1 



1 If it is desired to make a careful dissection of the air-sacs, dissect 

 away the muscles from the humerus, and cut that bone across a short 

 distance from its distal end : slip over the cut end a piece of indiarubber 

 tubing, to the other end of which is fixed a short glass tube : fix the 

 latter in a vertical position : make an incision into the trachea and 

 insert a cannula directed backwards, tying it securely : inject slowly with 



