- 5 - 
nicotine type, 21 5-224 °C.; (2) the mixed type, 190-215°, indica- 
tive of both elk^loids 8S mp.lor components; and (3) the nornicotine 
type, l 7 5-200*. Of 90 samples of tobacco examined, 2 were of the 
nornicotine type. One, Robinson's Maryland Medium Broadlesf, was 
investigated by ?/'arkwood (refs. 2_5 and £6 in E*56l) ; the other, 
Flue-cured Cash, may prove equally valuable as a source- material 
of nornicotine. Tiro tobaocos were of the mixed type; the others 
were of the nicotine type.— Markwood and Barthel (46) • 
The 42 species of Nicotiana , whan analyzed by an improved pro- 
cedure which is described, can be divided into 4 groups as follows: 
(l) The main alkaloid is niootine, seoondary pyridine alkaloids 
being absent or present only in insi^iificant quantities j (2) the 
main alkaloid is nornicotine, tertiary pyridine alkaloids being 
absent or present only in insignificant quantities; (3) a mixture 
of nicotine and nornicotine, and (4) the main alkaloid is anabasine. 
~ Shrouk and Borozdina ( 67 ) • 
A simplified method is presented for the identification of 
alkaloids of tobacco. The essence of the method is the formation 
of the picrates of the secondary base and submission of it to 
methylation without isolation of the pure auine; for effective- 
ness it is sufficient to have 2 to 10 mg. of the alkaloid. The 
picrate of the base is methylated quantitatively by heating with 
formaldehyde and formic acid. The presence of nornicotine by 
this procedure was shown in various members of the tobacco 
family. Determination of the picrate melting point both before 
and after methylation enabled the nornicotine to be identified 
in the presence of nicotine. Anabasine and piperidine nr^ also 
methylated by this procedure.— Shmuk (64). 
In order to find a more logical basis for a classification 
of tobaccos, the melting points' of picrates prepared from known 
mixtures of nicotine and nornicotine were determined. The steam- 
volatile alkaloids were separated from the plant material by dis- 
tillation and the melting point of the mixed picrates of the alka- 
loids was oompared with that of the known-mixture picrates. In 
the curve prepared from the known -mixture-pi crate melting points 
and composition the slope of the right-hand side was sufficient 
to warrant establishment of a division at composition two-thirds 
nicotine and one-third norniootine, and temperature 211° C. Hence, 
tobaccos, the alkaloids of which give a picrate with the upper 
limit of the melting range above this point, are considered as the 
"nicotine type. 1 * The division point at composition one-third 
nicotine and two-thirds nornicotine, and temperature 196° C, 
falls in a region of merked discontinuity of melting-point be- 
havior and is therefore even more suitable to set off the 
"nornicotine type" of tobacco. This leaves the interval 196° 
to 211° C. as characteristic of "mixed type" of tobacco. Tobaocos 
were analytod for nicotine and nornicotine, and the analysis and 
the melting point of the picrate of the steam-volatile alkaloids 
from the sample were oompared with the oomposition-melting point 
curve. The close agreement of the relative percentage compositions 
and melting points obtained from the tobacco samples with t..ose of 
known solutions has been used with considerable success in extimat- 
ing the relative composition of these alkaloids in samples. — Rowen 
and Barthel (15). 
