376 
B. MELLAND. 
part of the fibre is now in the centre of what was the bright 
band, that is, in the position of Krause’s membrane. Border- 
ing on this dark band, and separating it from the dim band, is 
a bright zone. The dim band remains much the same as 
before, though by contrast with the now dark Krause’s mem- 
brane it may appear lighter. 
The bright haloes round the nodal dots of the network may 
be compared with the similar effects observed whenever any 
highly retractile particle, such as a micrococcus or minute 
oil-globule, is observed in a medium of lower refracting 
index. 
In the oil-globule suspended in water similar and very 
definite transposition effects are seen on altering the focus. If 
focussed low it appears as a dark spot surrounded by a bright 
halo or border (l, diag. 7). On raising the objective (about 
•0025 mm., Zeis D) the oil-globule appears bright, surrounded 
by a dark border. 
The effect produced when a row of oil-globules are seen side 
by side is at the lower focus (l), a bright band (formed by the 
coalesced haloes) with a series of dark dots traversing it. At 
the upper focus (u) a narrower bright band, bordered by dark 
edges. The beads at the nodes of the transverse network may 
be looked upon as refracting and reflecting the light, in the 
same way as an oil-globule in water, and as causing the so- 
called “ transposition” of the bands seen on altering the 
focus. 
( b ) Bee. — Insect muscle may be very conveniently obtained 
from the thorax or leg of the bumble bee. 
Prepared with acetic acid and gold chloride, by the method 
already described, it shows a network identical with that 
described in Dytiscus. 
In order to obtain muscle in as uncontracted a condition as 
possible, gold preparations were made from the leg muscles 
of a bee, rendered insensible and immovable by chloroform 
vapour, in which presumably there was complete relaxation of 
the muscle-fibre. These preparations, however, could not be 
distinguished from those prepared without chloroform. 
