may be proved to one’s own satisfaction by experiments in 
a kitchen garden, providing one is careful to select plant material 
that is easily controlled, not easily affected by slight changes of 
environment, and normally self fertilizes (inbreeds) itself, yet is 
easy to cross. Varieties of peas are excellent material. 
The first of these statements can be demonstrated by making 
several cuttings of a pink-flowered hydrangea. All the cuttings 
from the same plant generally have the same hereditary units. If 
some of these cuttings are grown in ordinary soil and some are 
grown in soil strongly impregnated with alum water, both pink- 
flowered and blue-flowered plants will result, and the blue flowers 
will be the result of a change in environment. Figures 1 and 2 
represent the same conditions. The two parts of the same dande- 
lion plant were subjected to different environments. Pea seeds, 
from a variety breeding true to tallness, will demonstrate the same 
fact, as the seeds, if planted in poor soil, will produce dwarf plants. 
Figure 2 illustrates how red grains of corn may be produced 
through the action of sunlight. Ordinarily the mature grains of 
this variety are almost white, because the light is kept away from 
them by the husk. Figure 3 shows the variability of length of 
pods in a single pea plant. Environment is responsible for these 
differences in length. Figure 4 is a photograph showing the 
typical character of the pods in thirty or more varieties of garden 
peas, planted at the same time and growing under practically the 
same conditions of soil, climate, etc. The differences between 
these varieties as regards pod characters are due to different 
hereditary units. This is one of the many illustrations one might 
give of statement 2, as most garden varieties of peas have prob- 
ably arisen thru crossing. Figure 5 shows the results of crossing 
a pea with small pods with a variety having medium sized pods. 
The long row of pods is made up of a typical specimen from each 
of 15 second generation progeny, the first crossed generation not 
being represented. These two varieties evidently differed in many 
hereditary units for pod length. 
Statement 3 can be demonstrated by crossing tall and dwarf 
peas, and subjecting the second generation from such a cross to 
drought and poor soil conditions. If these are vigorously enough 
applied, all the peas will remain dwarfs; whereas three-fourths of 
them should be tall. 
Statement 4 is well demonstrated by two varieties of tobacco 
growing in the piant-breeding plots of the Brooklyn Botanic 
Garden. The individual plants of one of these varieties are sim- 
ilar to the parent plant from which the other variety originated. 
This parent type had from 18 to 24 leaves, a round stem and nor- 
mal 5-petaled flowers. The other variety, which originated from 
