92 PROGRESS OF MICROSCOPICAL SCIENCE. 
valence of malaria at certain seasons. The marshy pools formed 
in the Campagna during the winter months are found to swarm with 
alge, both green and colourless, in early spring. As summer ap- 
proaches, the level of the water in these pools sinks, owing to 
evaporation, and great sheets of dead and decaying alge are exposed 
to the air. In these, the spherobacteria grow and multiply; they 
may be found in vast numbers in the air to a height of fifty centi- 
meters above the surface of the marsh. Swept hither and thither by 
the wind, they excite malarial disease whenever they happen to pene- 
trate into the human body.” 
How Nerves end in Tendon.—The terminations of nerves in muscle 
has been carefully studied by Dr. Beale, F.R.S., and also by certain 
French and German observers. Their terminations in tendon is a 
subject of more novelty. It seems, according to a notice in the 
‘ Academy’ (December 9), that the tendon of the sternoradialis muscle 
in the frog receives a nerve-trunk of some size near its point of 
insertion; the fibres form a network, and end in the tendon. By 
employing special methods of examination, Rollett * has sueceeded in 
demonstrating that the ultimate fibres terminate in structures which 
he terms “ nerve-flakes,” and which present many points of similarity 
to the motor end-plates in striated muscle. Their functional signi- 
ficance is doubtful. No reflex movement can be produced by stimu- 
lating the tendon; hence Rollett concludes that the nerve must 
consist of centrifugal fibres. 
The Structure of the Optic Baton in Crustacea.—This part, which 
may generally be described as that portion of the eye — whether 
simple or compound —which extends from the cornea in front to the 
optic nerve behind, and which to some extent corresponds to our 
aqueous humour, has been fully described in a paper which has just 
been read before the French Academy of Sciences by M. J. Chatin. 
The author states that extending in the directions already indicated 
its appearance is filiform, and it may readily be divided into two 
distinct parts; the one external and hyaline—the cone, the other 
internal and notably elongated, and to this is given the special name 
of baton. Sometimes this latter is of the same diameter throughout ; 
at others it is wider at its terminal part, and often is subdivided into 
a series of prolongations over the surface of the cone. A pigmentary 
matrix surrounds the bdton, and communicates a deep tint to it, a tint 
which it is necessary not to confound, as is sometimes done, with the 
proper colour of the béton. This in many crustacea shows a series 
of transverse stri# and intermediate spaces which have led to the belief 
that it had a distinct muscular tunic. This idea the author thinks 
originated with the German school, which has generalized too much, 
and hence has established as facts what are mere suppositions. 
Besides, the work carried on by Germans, to which he refers, has been 
chiefly on insects alone, and he believes that he can mention certain 
facts which render a belief in the muscular filaments impossible. If 
* ‘Centralblatt,’ October 21, 1876. 
+ ‘Comptes Rendus,’ No. 22, t. 83. 
