390 Reed. — Some Points in the Morphology and 
deviates from the * usual ’ course of development because of its being 
subjected to new external influences, then the term abnormal should cease 
to have any meaning so far as that individual alone is concerned, for 
obviously if it has been caused to deviate from the usual path of develop- 
ment because of certain specific new conditions, then that altered form 
is merely a new form which fits in with new conditions ; that is to say, 
it is normal in so far as it is an individual which has developed as a 
result of inherent tendencies and external conditions, but abnormal when 
considered in relation to the ‘ type form \ 
Within recent years many experimental facts have been obtained 
which go to show the truth of de Vries’s suggestion. 
It has been shown by G. Klebs (10), amongst others, that an alteration in 
the nutrient medium of an organism may have an important effect upon the 
form or phase of life of the individual concerned, and A. F. Blakeslee (1) 
has shown that it is possible to cultivate distinct physiological races by 
varying the conditions of culture. Similarly with the variations in Oenothera 
Lamar ckiana^ which de Vries discovered near Amsterdam in 1 886. In 
its native soil the form had proved fairly constant, but in the potato field 
at Hilversum, where it met with new conditions, it soon began to assert 
its power to vary by producing ‘ abnormal ’ forms in the shape of fasciations 
and pitcher leaves, annual and triennial forms in place of biennials, and 
numerous other forms. 
While altered conditions of culture may only result in a temporary 
‘ variation ’ of the organism, it is important to notice that the individual can 
apparently be made to change in some degree. 
It does not seem to be a far cry from these altered forms to those 
recently obtained by D. T. MacDougal (12). This observer injected solu- 
tions of sugar, zinc sulphate, & c., into the ovaries of flowers of Oenothera 
biennis and Raimannia odorata , and from the ovules of these plants he 
obtained seeds which on germination gave rise to individuals which deviated 
to a considerable extent from the normal parental type. These observa- 
tions are particularly interesting in that not only were the individuals very 
different from the parental type, but also in that the derived forms have bred 
true over a period of five years. In other words, it would appear that 
we have here an ‘ abnormality ’ induced by a specific alteration of conditions 
of growth, i. e. an induced mutation. The ‘ derivative ’ form also breeds 
true to type when placed in the habitat of its parental type. 
In nature it is not always easy or possible to analyse all the factors 
which may be operating on the individual, but it seems probable that there 
must be factors the effects of which, either singly or collectively, may be to 
induce modifications in the organism. What the actual mechanism is would 
be difficult to determine. Is it a definite chemical action of the disturbing 
substance on the constitution of the plant body, or is it an alteration in the 
