64. 



jar contained a series of leaves some with the upper surface 

 free; some with lower surface uncoated; some with both upper 

 and lower surfaces clear and some v/ith both surfaces sealed 

 by the vaseline, It may be mentioned here that whij^e vaseline 

 was used in preference to cocoa butter since the latter tends 

 to harden, crumbles and drops off when the leaf begins to 

 curl thus introducing an error when the leaves are weighed. 

 All leaves of each series being in the same jar were exposed 

 to precisely the same drying conditions .The very dame experiment 

 was also made with leaves which had been previously killed 

 by being subjected to chloroform vapor for three hours, after 

 Y/hich time they became brown and began to curl, Thus, both 

 living and dead leaves were subjected to precicely the same 

 drying conditions, Each leaf from every desiccator was weighed 

 once in twenty four hours for one week. 



The third experiment was designed to determine any 

 internal structrual chaiges in the leaf under either dry (curled!) 

 condition or the moist (expanded) condition, Small pieces from 

 curled and expajided leaves were cut from plants gro;^-n in the 

 open, These were immediately dropped into absolute alchohol 

 and kept there for thirty siK hours frequently changing -the 

 alcohol to insure complete dehydration, The material was thus 

 fixed before any internal changes could take place, Later the 

 ordinary method was used in imbedding and sectioning this fixed 

 material, For fixing the sections on the slide no water v/as used, 

 nor was there any water or dilute alcohol used in the staining 



