Notes on Myriapoda. — - 1 
carpophagus from Darwen we made the examination of films 
of material obtained in the lighting condition in our holder. 
On staining by Gram’s method it was at once evident that 
Juminosity \ was not due to micro-organisms of the type known 
to occur in the blood of some Crustacea, and that if they 
were present at all they must be filter-passers. Experiments 
quoted by Dahlgren (4a), pp. 23-24, in another connection 
seem to show that no ereiete bacteria are known to him 
to be filter-passers. 
Thus our attempts to find micro-organisms that could 
cause luminosity have all failed, and we conclude that 
luminosity in Geophilus carpophagus appears to be an entirely 
physico-chemical phenomenon. 
The details of our experience in this matter confirm our 
view. ‘The fresh luminous discharge from a G. carpophagus 
stained by Gram’s method in search of micro-organisms was 
examined under the oil-immersion lens. The. appearance 
was tlat of innumerable very small (less than 0°75 pw) 
granules, round and regular and evenly distributed in the 
deposit. A few small irregularly distributed round empty 
spaces were also observed in the mass of stamed material. 
Were these very small granules luciferin granules or “ vacuo- 
lids” of Dubois? ‘Their regularity and minute size 
suggested a doubt. On the other hand, Would similar but 
non-luminous fluids exhibit hke staining properties? It 
happened that such questions were discussed with Mr. C. W. 
Ashton of the Manchester Royal Infirmary, and as an out- 
come an experiment was performed on the spot. ‘This 
experiment enables us to give a decisive answer to such 
enquiries. To a preparation of fresh egg albumin were 
added a few melted crystals of pure carbolic acid. A film 
was made from this bacteria-free acid albumin and stained 
by Gram’s method. Under the oil-immersion lens this film 
exhibited exactly simitar properties to those of the luminous 
discharge previously examined. 
The Physical Considerations. 
Radivactivity. 
As we turn to the physical aspect of the case, perhaps it 
will cross our minds at once that radioactivity may be the 
cause of luminosity. If so, the luminosity would be due, we 
suppose, to the bombardment of a fluorescent screen by a 
discharge from the radioactive material. It follows that the 
animal, in such circumstances, carries substances in its body 
which will produce or act as a screen. When our friend 
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