252 PLANT AND ORGANIC CHEMISTRY 



Comparing the Cycadeae and Palmae, the former are differ- 

 ently placed by different botanists, but the general resemblance 

 is remarkable, and they both yield sago. 



Chemical constituents of plants are found in varying quan- 

 tities during stated periods of the year. Certain compounds 

 present at one stage of growth are absent at another. Many 

 facts could be brought forward to show the different chemical 

 composition of plants in different stages of growth. The Thuja 

 occidentalism in the juvenescent and adult form, offers an ex- 

 ample where morphological and chemical differences go hand 

 in hand. Analyses of this plant under both conditions show 

 a striking difference. 



Different parts of plants may contain distinct chemical com- 

 pounds, and the comparative chemical study of plant orders 

 comprises the analysis of all parts of plants of different species. 



For example : four portions of the Yucca angustijolia 2 were 

 examined chemically the bark and wood of the root and the 

 base and blades of the leaves. Fixed oils were separated from 

 each part. These were not identical, two were fluid at or- 

 dinary temperature, and two were solid. Their melting and 

 solidifying points were not the same. 



This difference in the physical character and chemical re- 

 action of these fixed oils may be due to the presence of free 

 fatty acid and glycerides in varying proportions in the four 

 parts of the plants. It is of interest to note that, in the subter- 

 ranean part of the Yucca, the oil extracted from the bark is 

 solid at the ordinary temperature; from the wood it was of a 

 less solid consistency; while the yellow base of the leaf con- 

 tained an oil quite soft, and in the green leaf the oil is almost 

 fluid. 



Two new resins were extracted from the yellow and green 

 parts of the leaf. It was proposed to name them yuccal and 

 pyrophaal. An examination of the contents of each extract 

 showed a* different quantitative and qualitative result. 



Saponin was found in all parts of the plant. 



Many of the above facts have been collected from the in- 



1 Meehan, Proc. Acad. Nat. Sciences. 



2 H. C. De S. Abbott, Trans. Amer. Philos. Soc., 1886. See p. 126. 



