430 
POPULAE SCIENCE EEVIEW. 
within the rostellum attached to the saddle-shaped disc alone, and surrounded 
by fluid, so that the viscid matter does not set hard till the disc is withdrawn. 
Then we have the upper surface of the saddle, with its attached caudicles, 
also kept damp within the bases of the anther-cells, until withdrawn, when 
the curious clasping movement instantly commences, causing the poUinia to 
diverge, followed by the movements of depression, -which compound move- 
ments together are exactly fitted to cause the ends of the two poUinia to 
strike the two stigmatic surfaces. These stigmatic surfaces are sticky enough 
not to tear ofl' the whole pollinium from the proboscis of the moth ; but, by 
rupturing the elastic threads, to secure a few packets of pollen, leaving plenty 
for other flowers. But let it be observed that although the moth probably 
takes a considerable time to suck the nectar of any one flo\ver, yet the move- 
ment of depression in the poUinia does not commence until the poUinia are 
fairly drawn out of their cells, nor will the movement be completed and the 
poUinia be fitted to strike the stigmatic surfaces until about half a minute 
has elapsed, which wUl give ample time for the moth to fly to another plant, 
and thus elfect a union between two distinct individuals. 
We need not advert to tUe experiments instituted to prove 
tliat the agency of insects was essential for the fertilization of 
all the British species of the genus Orchis. W e cannot, how- 
ever, entirely pass the subject of the production of nectar in 
the nectaries of Orchids, to which our author devoted consi- 
derable attention. Having examined several species, and 
found no signs of nectar either in the nectaries or labellum, 
although the plants must have existed for enormous periods of 
time, requiring for each generation insect agency, and possess- 
ing special contrivances for that purpose, he still pursued the 
investigation with faith that the nectaries could not be a sham, 
or that the plants existed by an organised species of decep- 
tion. 
As soon as many flowers were open [he says] I began to examine them. 
For twenty-three consecutive days I looked at them after hot sunshine, after 
rain, and at all hours. I kept the spikes in water, and examined them at 
midnight and early in the morning. I irritated the nectaries with a bristle, 
and exposed them to irritating vapours. I took flowers which had quite 
lately had their poUinia removed by insects (of which I had independent 
proof on one occasion by finding within the nectary grains of some foreign 
pollen), and I took other flowers which from their position on the spike would 
soon have had their poUinia removed ; but the nectary was invariably quite 
dry. 
Convinced tbat tbe nectaries of these particular species of 
Orchids never contained nectar in this country, he next ex- 
amined the membranes lining them, and was surprised to find 
' that the outer and inner membranes were separated from each 
other, and contained a quantity of fluid between them ; more- 
over, that the inner membrane was exceedingly delicate ; and 
