XXXVI, bottom left) were found to represent Ipomoea 
violacea L. (204 g.). 
The first small samples were sufficient for a number of 
chemical-analytical experiments, which showed the pres- 
ence of indole compounds. This interesting result induced 
us to order greater quantities of these two seeds from 
Wasson. This second, large contingent of seeds (12 kg. 
of seeds of Rivea corymbosa and 14 kg. of Ipomoea violacea) 
was obtained with the aid of the Weitlaners, about whom 
Wasson gave the following information to the writer in 
a letter of 10th December 1959: ‘‘Robert Weitlaner is 
an Austrian, a naturalized Mexican citizen... Heisa 
field anthropologist and likes being in the field much 
better than lecturing to the students in the Instituto 
Nacional de Antropologia e Historia, where he has a 
post. He is past 70 already, but still goes out for months 
at a time with almost no luggage, living in the villages. 
Irmgard is his daughter, the native-textile expert of the 
Museo Nacional... ’’ These Rivea seeds obtained with 
the aid of the Weitlaners were gathered in the vicinity 
of Ocozocoautla (Chiapas), the Ipomoea seeds in the 
Zapotec region by Thomas MacDougall and Francisco 
Ortega. 
In 1960, MacDougall published his important dis- 
covery that, especially in the region of the Zapotecs, the 
seeds of a second twining species, which he found to be 
Ipomoea violacea, were used in conjunction with or in- 
stead of ololiuhqui.” 
By using the large quantities of seeds of Rivea corym- 
bosa and Ipomoea violacea, which we received in the early 
part of 1960 in the manner already described, we were 
able to isolate the main active principles and identify 
these chemically during the course of the summer. This 
isolation and identification will be reported in detail be- 
low. In a number of ways, the results of these investi- 
[ 199 | 
