January, 1915.] THE ORCHID REVIEW. 23- 
dressing with a mixture of osmunda fibre and sphagnum moss will suffice,. 
but if the drainage is imperfect, or the compost sour, then the plant must 
be repotted. Afford plenty of drainage materials, and after repotting keep- 
the surface of the compost just moist until new roots are seen pushing their 
way into it. Small, well-rooted plants of O. Edwardii, having the surface 
of the compost in a fresh, healthy condition, and the growing sphagnum 
moss closely clipped down on to the soil, form a very suitable place to sow 
seed on of almost all cool-growing Orchids. The seeds should be spread. 
very carefully and thinly over the surface, and be kept fairly moist at all 
times. A small propagating case at the warmest end of the Cool house is a- 
suitable place until the young seedlings make their appearance, and after a. 
short time the seed pots may be removed and placed in a somewhat lighter 
position in the same house, where they can be conveniently attended to. 
Should damp appear among the small seedlings during their early stages,. 
it is advisable to remove them to a more airy position, and to elevate them 
a trifle nearer to the roof glass, and at the same time to keep them less. 
moist. 
SOPHRONITIS.—In this house plants of the glowing scarlet Sophronitis- 
grandiflora will now be in bloom, and few if any Orchids produce a more 
brilliant effect than well-flowered plants of this species. The plants are 
best grown in well-drained shallow pans, using but a very thin layer of 
osmunda fibre for them to root in. Repotting may be done as soon as- 
growth commences, or immediately after the flowers fade. During growth 
they need to be well supplied with water, less sufficing when the small. 
pseudobulbs are fully made up. S. cernua, now seldom seen in bloom,. 
requires the same treatment, but large flat imported pieces thrive best 
when fastened to teak boards, with a little compost to assist in keeping 
them moist. S. violacea, which is a pretty little species, does better when 
grown in the coolest part of the Intermediate house. 
THE VIGOUR OF HyBriDs.—Can you tell me, asks a correspondent, why 
it is that primary hybrids are nearly always more vigorous than their 
parents? We believe it is due to the reaction caused by differences in the 
constitutions and habits of the two parents, which sets up a constant 
stimulus to development. It is precisely parallel with the well-known 
benefits secured by cross-fertilisation. Darwin regarded it as essentially 
related to the principle of life, this principle, according to Mr. Herbert 
Spencer, consisting in ‘‘ the incessant action and reaction of various forces, 
which, as throughout nature, are always tending towards an equilibrium; 
and when this tendency is slightly disturbed by any change the vital forces 
gain in power.’’ Crossing secures those changes in the conditions of life. 
which are believed to benefit all living things. 
