# 
= “Monthly Microscopical Journal” a thread-worm (Filari 
~ miis), infesting the vascular system of the dog, and thus 
oe blood, isan entrance into the system. “The faculty 
Nuphar. The whole interior of the leaf is studded with them. — 
_ the lake, buoyed up by innumerable life-preservers which are not 
Hunt, M.D. 
250 MICROSCOPY. 
the edge of the glass. The microscope being arranged for draw- — 
ing and an object focussed, this tube was adjusted and the oblique 2 
end smeared with glue; then the disk was fitted to the end-of the 
tube in such a manner that the bit of mirror was in its optical 
axis. After the glue was dry the projecting edge of the disk was 
removed and the eye end of the apparatus cut down so that the 
eye might approach the reflecting surface. This works nicely, 
and is much more easily made than the brass mounting.—F. B. — 
Kimpatyt, M.D. A 
AIR-CELLS IN A FLoatine Lear.—In the leaf of Limnanthemum — 
lacunosum, or floating-heart, may be demonstrated multitudes of 
peculiar stellate bodies, apparently like those found in the stem of — 
Tees 
There are no ordinary large air-spaces so_often found in other | 
floating leaves, but all through the parenchyma these curious bod- 
ies are irregularly scattered. : 
They vary in size and also in the number of rays given off by — 
each. These rays are smooth and not echinulate like those in — 
Nuphar. In the field of a % lens I have counted hundreds at one — 
view. Under the polarizing binocular microscope properly illu- 
minated, they are revealed with startling distinctness and beauty. 
- It is nearest the under epidermis that they are located, and the 
best view therefore is obtained from beneath. Their true physio- 
logical significance is not doubtful. In the natural condition they 
contain air, and the floating-heart rides securely on the surface 0 
likely to shift out of place. 
e veins in the leaf are present, of course, but are compara- 
tively rudimentary. The vascular bundles are faintly marked, and 
only a few delicate supporting cells line their margins ; thus giving 
another example of nature’s economy, for where strongly 
oped organs are not necessary there we fens not find P =h 
Lire or Hæmarozoa. — Francis H. Welch describes in 
rizes as to the method by which such parasites, which are 
doubly interesting from having, been recently discovered in 
