342 



Ibervillea Sonorae 



weighed in porcelain crucibles as rapidly as possible. Each 

 sample was dried to constant weight in an air bath at ioo° C, in 

 which process all water was removed. The weight of the dry 

 solid matter was taken and, after complete incineration at a low 

 temperature, the weight of the ash was also noted. The follow- 

 ing weights and percentages were recorded in this connection : 



RECORDED ANALYTIC DATA. 



Tuber Fresh substance. Dry substance. Ash. 



Sample. grams. grams. gram. 



1 12.0060 1.6690 0.1710 



2 15.4403 1.9223 0.2203 



3 19.3512 2.3222 0.3822 



4 14.9534 1.9834 0.2144 



Average 15.4377 1.9742 0.2219 



GENERAL PERCENTAGE COMPOSITION. 



Tuber Organic 



Sample. Water. Solids. matter. 



1 86.10 13.90 12.49 



2 87.56 12.44 11.02 



3 88.00 12.00 10.60 



4 86.74- 13.26 11.82 



Average 87.10 12.90 11.48 1.42 



V. GENERAL QUALITATIVE COMPOSITION. 



In an endeavor to ascertain the character of the more conspicu- 

 ous constituents of the tuber, grouped under the general term 

 "solids," various extracts were made and tested. Between the 

 arrival of the tubers from Sonora and the time when they were 

 used for this study (almost a year) , they remained in the labora- 

 tory on saucers, without earth or water, and seemed to keep per- 

 fectly, one even putting out several shoots during the summer.^ 



Preparation of material. In the preparation of the tuber for 

 these tests, dirt and dust were brushed off and the tuber was 



(Fig. B) would indicate that the swollen portion includes root, hypocotyl 

 and stem. * * * The formation is stem and at least half of the swollen 

 portion may claim that distinction. — Knox, loc. cit., p. 340. 



* The quantitative data recorded above were obtained from tubers in the 

 same general condition. 



