Notes . 
588 
Bacteria have direct infective properties as regards crabs and other 
marine animals. 
These organisms require particular and exact conditions in order 
to exhibit their luminous properties. They must have a suitable 
nutrient soil containing such proportions of salts as shall render 
the medium isotonic. For example, sodic chloride, if present to 
the extent of 3 per cent., will render the organisms luminous and 
ensure their remaining so for some time. In this manner they can 
be readily cultivated and studied in the laboratory. 
The luminosity appears to be a function of the living cell and can 
be disturbed by any process which interferes with the vitality of the 
cell itself. The dead cell is non-luminous, whilst antiseptics which 
kill the cells inhibit at the same time their luminosity. 
A supply of free oxygen is essential ; in the absence of oxygen the 
organisms live but are non-luminous. There is no evidence of a 
bacterial product as the source of the light. The process appears 
to be the result of an active oxidation occurring within the cell. The 
light produced is confined to a small portion of the visible spectrum, 
and invisible radiations have not been detected. As the spectrum of 
none of these luminous organisms extends even to the red, it may 
safely be assumed that no heat radiations are emitted. The light is 
produced without heat. No invisible radiations allied to the X-rays 
were detected. Photographs have been obtained by the aid of the 
light emitted by these organisms. The time-exposure required is, 
however, considerable. 
An exposure to the temperature of liquid air does not destroy th e 
luminosity of the organisms. It has been found possible to triturate 
Bacteria at the temperature of liquid air by means of special methods 
devised at the Jenner Institute of Preventive Medicine. The luminous 
Bacteria mechanically broken up in this manner ceased to phosphoresce. 
The luminosity, therefore, is due to the vital processes of the cell, 
and essentially depends for its origin on the intact organization of 
the cell. 
We have brought these results forward because this interesting 
group of organisms have not hitherto been studied in this country 
so far as we can trace. 
Jenner Institute. 
J. E. BARNARD. 
ALLAN MACFADYEN. 
