THE CHAULMOOGRA TREE AND RELATED SPECIES. 9 
II.— HYDNOCARPUS OIL. 
The first hydnocarpus oils to be completely investigated were those 
expressed from the seeds of Hydnocarpus wightiana Blume and 
H. ant helminthic a Pierre (18) . They were found to resemble chaul- 
moogra oil very closely, both in their physical characters and in their 
chemical composition. Like the true chaulmoogra oil (from Tarak- 
togenos) , they consist to a large extent of the glyceryl esters of chaul- 
moogric and hydnocarpic acids, and it may therefore be inferred 
that they possess similar medicinal value. The fatty oils obtained 
from the seeds of these two plants have, indeed, long been used in 
western India and in China for the same medicinal purposes for 
which chaulmoogra oil is employed. 
De Wolff and Koldewijn (25) determined the physical constants 
of the oil from Hydnocarpus alpina Wight and found them to agree 
rather closely with those of chaulmoogra oil. The oil from Hydno- 
carpus venenata Gaertn. was shown by Brill (4) to contain both 
chaulmoogric and hydnocarpic acids, and the same investigator has 
stated (5, p. 45) that more than 90 per cent of the free acids from 
the oil of Hydnocarpus alcalae C. DC. consist of a compound identical 
in properties with chaulmoogric acid. 
III.— GYNOCARDIA OIL. 
Gynocardia oil is obtained by expression from the seeds of Gyno- 
cardia odorata E. Br., which do not appear to be collected for 
commercial purposes. Prior to the year 1900 it was generally be- 
lieved that the chaulmoogra oil of commerce was obtained from 
this botanical source, and the terms " chaulmoogra oil " and " gyno- 
cardia oil" were therefore considered to be synonymous. This con- 
fusion became extended to the fatty acids, in so far that an in- 
definite mixture of acids from chaulmoogra oil was designated many 
years ago as " gynocardic acid," and this misnomer is still frequently 
encountered in current literature. It has, however, been shown, 
as noted in this bulletin, that the true chaulmoogra oil is obtained 
from the seeds of Tarahtogenos hurzii King, and this botanical ob- 
servation was confirmed by a chemical examination of the oil from 
carefully identified Taraktogenos seeds. This perfectly authentic 
product was moreover found to agree in character with the chaul- 
moogra oil of commerce. On the other hand, it was subsequently 
shown that the oil expressed from freshly collected and carefully 
identified seeds of Gynocardia odorata differs completely from 
chaulmoogra oil, both in its physical characters and in its chemi- 
cal composition (18, p. 896). 
Gynocardia oil at ordinary temperatures is a pale-yellow liquid, 
having an odor resembling that of linseed oil. The specific gravity 
83466—22 2 
