GROWTH 2% 135 
food. Some time in February the Hyacinths will probably | 
flower, and then they may be compared. It will be found 
that the one grown in the dark has a longer and more 
straggling stem than the one grown in the light. The leaves 
are yellow, not green, for, owing to the absence of light, the 
dark green colouring matter has 
not been formed. The one grown 
in light has dark blue flowers, and 
the other a very pale bluish flower, 
almost colourless. | 
Sometimes Hyacinths which 
have been grown in the way just 
described do not give the expected 
results, and then it will be found 
that the other conditions have not 
been similar, Perhaps the one in 









Fic. 147.—SEEDLING OF 
PEA GROWN IN LIGHT. 
the window has heen 
exposed to a different 
temperature than the 
one in the cupboard, 
or the latter may not 
have had as much free 
oxygen as the former. 
It is very important in comparing the effect of light and dark- 
ness on growth to try and secure that the other conditions be 
exactly similar. A good way of securing this is to take a 
growing plant, such as a Vegetable Marrow or Potato, and 
to introduce the growing point of the stem into a cardboard 
10—2 
Fic. 148.—SEEpLING oF PEA GROWN IN 
DARK. 
