Julia T. Emerson and William H. Welker 345 



diastatic and oxidative enzymes appeared to be absent. It is 

 possible that the conditions of the tests were not favorable to 

 digestive results, although ordinary methods were used. 



Basic substances. A few tests for alkaloids, with the so-called 

 alkaloidal reagents, in extracts free from coagulable protein, 

 gave indications of the presence of basic substances (see p. 346). 



Chlorophyll was conspicuous in the subcortial tissue. 



VI. TOXICOLOGICAL NOTES. 



In Mexico where Ibervillea SonorcB grows in abundance, the 

 natives consider it poisonous. Watson' has stated that "a 

 decoction of the root is used as a cathartic." 



Preliminary toxicological experiments on frogs. Several pre- 

 liminary tests of the toxicity of the tuber were made on frogs, by 

 injecting under the skin or into the stomachs small volumes of 

 concentrated aqueous solutions of dry residues from alcohol or 

 ether extracts, with the following results: 



(a) Residue from alcohol extracts. First frog: Introduction 

 per OS. No visible effects. Second frog: Injection subcutane- 

 ously. Spasms occurred in a few minutes ; later there was retch- 

 ing. Death ensued in three hours. 



(6) Residue from ether extracts. Third frog: Introduction 

 per OS, about 3 p.m. There were signs of nausea during the after- 

 noon. Death occurred during the night. Fourth frog: Injec- 

 tion subcutaneously. Convulsive movements preceded death in 

 2^ hours. 



The results of these tests led us to look for alkaloids. For the 

 preliminary isolation of any of the latter that might have been 

 present in the tuber we proceeded as is indicated below: 



Tests for alkaloids. The Stas-Otto method was employed for 

 the preparation of the extracts to be tested. The interior por- 

 tions of two tubers were finely minced and subjected to extraction 

 separately. Two alcoholic extracts were made of each. The 

 residues from each yellow alcoholic extract, which were obtained 

 by evaporation in vacuo at 40° C, were treated with absolute 

 alcohol, filtered and again evaporated to dryness. The residues 

 from the absolute alcohol were treated with water, the filtered 



' See p. 340. 



