32 F. C. STEWARD AND J. K. POLLARD 
occurs in quantity in Convallaria (see Fig. 4) and in many other liliaceous plants 
(see Table I). 
Substitution in the piperidine ring, foreshadowed by the discovery of baikiain (see 
Fig. 5), is seen by the presence of 5-hydroxypipecolic acid in legumes (Figs. 5 and 6) 
and in dates (Fig. 7) not to be a isolated occurrence. As yet, the analogous situation 
in the proline and azetidine rings are not known, for hydroxyproline seems to arise 
in other ways (POLLARD AND STEWARD?3). The photographs of the typical chromato- 
grams (which are here published as Figs. 4-8) not only show the location of these 

Fig. 7. The ninhydrin-reactive, alcohol-soluble compounds of the edible date. Spots designated by 
numbers 2—23 follow the same convention as in Fig. 1, but on this chromatogram leucine (18B) and 
isoleucine (18A) were separated. Note the occurrence of three piperidine derivatives. 
compounds on, papers prepared from extracts of the plants in question, but they em- 
phasize how prominent these compounds are in the soluble nitrogen fraction of the 
organs in question. 
The above shows that attention was early directed to the legumes because of the 
new compounds that were disclosed when extracts of these plants were chromato- 
graphed. Other examples of compounds disclosed in this way will be mentioned below. 
Maps, compiled by BarraLes® of unidentified ninhydrin-reactive compounds 
that had been revealed up to 1959 in this laboratory alone by the work of ZACHA- 
RIUS*®, GROBBELAAR™ and BARRALES (see Fig. 2) had upon them some 39 distinct 
locations. 
The rich variety of free nitrogen compounds to be detected in this way can be 
illustrated by observations made on phenol—H,O: butanol-acetic acid chromatograms 
of Saraca indica seeds (Fig. 8) by BARRALES® with one of us (F.C.S.) This chro- 
matogram showed three clearly defined but unidentified substances ; some of the more 
usual constituents of such extracts; the now not unexpected and conspicuous amount 
References p. 42 
