No. 446.] 



PHOV'JAl'S M A Ri:i XI'.LI C 



the opinion that the tracheoles do not coiilciin an , !)ui a rolorU-ss 

 fluid. Wielowiejski also found tlicm tilK'd with a lliiid, l)iit 

 recognizing the extreme improbability ol siu h roiuliiion rxisiin;; 

 in hfe, he looked for some explanation ot it. In diu'd. an iilud 

 material mounted in weak glycerine thf traclu'oK s as well as tin- 

 larger tracheal tubes were tilled with air. .\ttci ahoiit 

 minutes the silvery, glistening lines ot an iKHanir hiMkc-n up. 



and gradually, from the tracheoles in, the tracheae became filled 

 with a fluid. This would seem to prove, what one must believe 

 a priori, that the entire tracheal .system is filled with air . My 

 observations agree with Wielowiej ski's, for although in my 

 preparations the tracheoles were always already filled with liquid, 

 the penetration of the liquid into the larger branches was unmis- 

 takably from the tracheoles in. It may be noted ni this con- 



