uch as the production of continuous series of successive or
simultaneous sounds and of articulate speech.

The diaphragm serves but to increase the intensity of these effects, as
in the transmitter, by concentrating the lines of force of the field, and
by presenting a greater surface to the air--the necessary vehicle of
sound. When it is thick, the internal motions that it takes on in
consequence of variations in the field, and which are transmitted to the
surrounding air and the ear, are solely those of resonance. When it is
very thin, the peculiar motions resulting from its geometric form and its
structure may become superposed upon the preceding, because it may then
happen that the corresponding sounds remain within the limits of the
pitch wherein the human voice usually moves (from ut_{2} to ut_{5});
but then, also, as the harmonics of the voice in nowise coincide with the
proper sounds of the diaphragm, the intensity of the effects is obtained
at the expense of a good reproduction of the timbre. This is certainly
one of the causes of the nasal timbre of most thin-diaphragmed
telephones. By diminishing their thickness, we lose in quality what we
gain in intensity.

But even in this latter respect there is a maximum for receivers, as I
have already pointed out that there is for iron filings transmitters. For
a magnetic field of given intensity, there is, all things equal, a
diaphragm thickness that gives a maximum telephonic result. Such result,
which is analogous to those that occur in other electro-magnetic
phenomena, may explain the want of success of many tentatives made
somewhat at haphazard, with a view to increasing the intensity of
telephonic effects.

* * * * *

DECOMPOSITION AND FERMENTATION OF MILK.

Dr. F. Hueppe, who has paid great attention to this subject, describes
five distinct organisms which he finds to be invariable accompaniments of
lactic fermentation. One of these he isolated on nutrient gelatine in the
form of white, shining, flat, minute beads. This organism has the power
of transforming milk sugar and other saccharoses into lactic acid, with
evolution of carbonic acid gas. It is rarely found in the saliva or
mucilage of the teeth. In these are two micrococci, both of which cause
the production of lactic acid, but which manifest differences in their
development under cultivation. There are also two pigment forming
bacteria, _Micrococcus prodigiosus,