464 BOTANICAL GAZETTE [NOVEMBER 
one basic invariable unit determining the presence or absence of a character, 
plus numerous modifying factors; the number of the latter present in a given 
case determines the degree of expression of the character. The author admits 
that such modifying factors have been demonstrated in Drosophila, but goes 
on to show how “the objections raised by the mutationists to gradual change 
through selection are breaking down as a result of the thoroughness of the 
mutationists’ own studies.” For in Drosophila there have gradually been dis- 
covered not only 7 modifying factors for eye color, located on different regions 
of chromatin from the basic factor for eye color, but also 7 grades of the basic 
factor itself, that is, different conditions of the same unit. “What more does 
the selectionist want ? Is not the controversy at an end?” 
ere still remains, however, a fundamental difference between the two 
views. The selectionists claim that these changes (in unit characters) are 
continuous, and in a definite direction determined by the standard of selection. 
The mutationists, on the contrary, claim that these changes occur in distinct 
steps (mutations), and do not occur in any definite order or direction as the 
result of selection. JENNINGS takes exception to this last claim of the muta- 
tionists, and presents some of his work on protozoa, to show the effectiveness 
of selection in a series of asiaeorene generations. 
There is much to be d din sucha iliation between the two schools, 
but more evidence must come in before there can be much hope of bringing it 
about. At present the views of the mutationists seem to be in better favor, 
chiefly because they give a much more definite basis for description of the 
phenomena of inheritance. “If one creates a hypothetical unit by which to 
describe phenomena and this unit varies, he really has no basis for description 
(East).”—MERLE C. CouLter. 
Narcotic plants and stimulants.—Sarrorp® has published a very instruc- 
tive account of plants used by the “ancient Americans” as sources of narcotics 
and stimulants long before the discovery of America. He indicates 13 such 
plants as chiefly in use, among them Nicotiana, Datura Stramonium (a source 
of atropine), Erythroxylon Coca (a source of cocaine). Other plants of minor 
importance are also noted. In concluding the summary, the following state- 
ment is made: ‘In view of the shortage of medicinal alkaloids resulting from 
the present war, it is suggested that investigations be made to determine the 
nature of the properties of these less-known narcotics, with a view to their 
utilization as substitutes for others now recognized in the standard phar- 
macopoeias.””— < 
9 Sine FFORD, W. E., Narcotic plants rag = of the ancient Americans. 
Smithson. Rep. 1916. pp. 387-424. pls. 1 
