346 Miscellaneous. 



arises from a bad interpretation of a well-known fact. When wo 

 crush a glowworm we most commonly see luminous traces persisting 

 on the ground ; from this it has been concluded that the case of its 

 apparatus was the same as that of matches, and that these traces 

 were nothing but a phosphorescent material accumulated in the 

 apparatus for the ulterior needs of the insect. The experiment thus 

 made is very defective ; let us repeat it more methodically. If we 

 confine ourselves to tearing up, -with needles, a phosphorescent glow- 

 worm, the fragments remain luminous, at least for some hours. On 

 the other hand, if we rapidly crush one of these insects in a mortar, 

 so as to destroy the cells themselves, the phosphorescence immedi- 

 ately disappears ; and the pulp, if collected, exposed to contact 

 with pure oxygen, and subjected to the influence of electrical exci- 

 tation, remains absolutely dark. Thus a partial crushing allows the 

 phosphorescence still to be produced ; complete crushing abolishes 

 it. Upon the hypothesis of a store of phosphorescent matter, crush- 

 ing carried very far would evidently be favourable to the production 

 of light by spreading this matter over a large surface in contact with 

 air ; but the reverse of this takes place ; the phosphorescence does 

 not persist unless the apparatus is only reduced to fragments. This 

 is due to the fact that groups of cells remaining intact continue to 

 live and perform their functions. Tearing and the abnormal con- 

 tact of the air excite them ; and their protoplasm, reacting under 

 these influences, produces the phosphorescent matter at the ex- 

 pense of the materials which it contains. If we kill these cells 

 by crushing them, life no longer intervenes to set these materials 

 at work and give them the chemical form under which phosphores- 

 cence can manifest itself. 



We are therefore here in presence of a chemical phenomenon, 

 but of one which is not produced in the glowworm, except under 

 biological conditions. We can, moreover, prove this in another 

 manner. Besides crushing, certain toxical agents have the power of 

 destroying the cells. If we submit a glowworm to the action of 

 sulphuretted hydrogen it is killed immediately. If we then take it 

 and excite it electrically we obtain no light. The cells are intact 

 as to their form, but physiologically destroyed ; they no longer func- 

 tion. We may then tear the organ, and apply the action of oxygen 

 and of electricity without provoking phosphorescence. It is certain, 

 nevertheless, that this protoplasm contains all the materials chemi- 

 cally necessary for the production of the phosphorescent substance ; 

 but this substance is not ready made. It is only produced in 

 proportion to the waste, under the influence of the will and 

 Dy the intermediation of the nervous system, which excites the 

 cells and causes them to enter into action. Phosphorescence is 

 consequently a phenomenon of the same order as muscular move- 

 ment, or the evolution of electricity in the apparatus of the torpedo, 

 which are undoubtedly the result of chemical combinations taking 

 place in the protoplasmic matter. 



It is very probable that this phosphorescent substance is a 

 gaseous product ; for the structure of the gland, well investigated by 

 Owsianikow, does not give us the idea of an organ with a liquid 



