| 
Marcu 7, 1912] 
NATURE 
zl 
The collections included a large series of fishes and 
invertebrates, which have been handed over to the 
Indian Museum to be worked out. 
Only a short time could be devoted to the fisheries 
of the Sandarbans, that vast area in the Ganges delta 
which includes large rivers and pestiferous creeks 
where fish-life is impossible, but such observations as 
could be made indicate that here too profitable 
fisheries could be established, for it is to the Sandar- 
vans that the hilsa (Indian shad), one of the most 
esteemed of Calcutta food-fishes, resorts for the pur- 
pose of spawning . 
As a preliminary to the development of the rich 
fisheries of Bengal, it is recommended that a 
Fisheries Department should be established by the 
Indian Government without delay. Reale: 
DISINTEGRATING BACTERIA AND OTHER 
ORGANIC CELLS. 
BACTERIAL toxins may be broadly divided into | 
two varieties. In one of these the toxin is ex- 
creted into the medium on which the organisms are 
cultivated, and in the other type the toxin is retained 
within and forms an integral part of the living bac- 
terial cell. 
It is now generally recognised that the diseasc- 
producing effects of pathogenic micro-organisms are 
almost entirely due to the toxins, whether intracellular 
or extracellular, which they secrete. For immunising 
purposes or for the preparation of anti-sera, the toxin 
which is excreted may be obtained from the culture 
medium by filtration through a porous porcelain filter, 
such as the Pasteur-Chamberland, the organisms being 
retained by the filter and the toxin passing through. 
The diphtheria and tetanus bacillus are examples of 
this type. 
The majority of micro-organisms, however, do not 
excrete their toxin, at least to any extent, and among 
those that retain it within the cell are typhoid, cholera, 
plague, glanders, B. coli, B. streptococci, B. staphylo- 
cocci, &c. In these cases some method of rupturing 
the cell-wall, so that the contents may escape, has | 
been found to be desirable. This allows of not only 
the use of the toxin as such, but also renders it pos- | 
sible to investigate the chemical composition and pro- | 
perties of the bacterial proteins and other cell con- 
stituents. 
The apparatus to be described fulfils the required | 
conditions, and causes the cell-wall to be ruptured so 
that the contents are obtained unaltered. It is neces- 
sary that there should be no appreciable rise of tem- 
perature during the operation, apart even from any 
extraneous cooling arrangement, or else chemical 
change would occur; the apparatus therefore must be 
so far as possible frictionless. Every organism must 
come under the grinding action, so that either no 
whole cells remain or their number is reduced 
to a minimum. The containing vessel in which the 
grinding action takes place must be so effectually 
sealed that, during the process of disintegration, no 
cells have any opportunity of escaping. This applies 
particularly when pathogenic organisms are being 
dealt with. The apparatus as designed is made in 
two forms; in one (Fig. 1) it is mounted between 
horizontal centres, and in the other (Fig. 2) between 
vertical centres. In the former the grinding action 
is controlled by gravity, and in the latter by electro- 
magnetic means. : 
The appliance consists essentially of a phosphor 
bronze or steel pot or vessel, A, in which a number 
of steel balls, B, are allowed to revolve. The steel 
balls accurately fit the inside of the containing vessel, 
so that as the machine rotates they are in contact 
NO. 2210, VOL. 89] 
over nearly one-half of their circumference with the 
inside of the vessel. A metal cage, C, is made of such 
a shape that its prongs lie between the balls, so that 
the latter cannot collide one with another when the 
machine is rotating. Mounted at the centre of the 
metal vessel is a steel cone, D, which is of such a 
size that it keeps the balls in their proper position in 
close contact with the periphery of the containing 
vessel. This cone is an important part of the 
apparatus as upon it depends the pressure that may 
be exerted on the balls; and, further, as the result 
of its use the balls themselves have freedom to slip 
Fic 1. i 
if any additional strain is thrown on them, or if any 
undue amount of material comes under their action. 
The containing vessel is closed by a metal cap, E, 
which screws down, hermetically sealing the vessel. 
A groove is made in the top of the containing vessel 
into which a lip on this screw cap loosely fits. 
Sufficient space remains between the two, as shown 
in the figure, to allow of some bacterial agent being 
placed therein, thus effectually preventing the escape 
of whole bacteria or ground material from the contain- 
ing vessel. Over the whole of this a cylindrical cap, 
F, is placed, and in the top of this cap a metal cone, G, 
is fitted, which presses by means of a spring on to the 
top of the steel cone, D. The steel cone is itself 
hollow, and is closed by a small metal cap, L. A 
lead or steel weight, K, is fitted on to the steel 
spindle, D, and is clamped on any desired position 
along it. 
The apparatus is mounted on a cone, H, and runs 
between this cone and the centre, I. It may be con- 
veniently connected directly up to a motor, as shown 
in the illustration, or may be driven by a belt from 
any suitable source of power by putting a grooved 
pulley on to the left-hand end of the spindle. 
The grinding action takes place between the steel 
