The flea / by Harold Russell.

  • Harold Russell
Date:
1913
Catalogue details

Licence: In copyright

Credit: The flea / by Harold Russell. Source: Wellcome Collection.

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    fleas put in could be recovered, and no fleas were ever found alive after the fifth day. The European rat-flea {Ceratapkyllus fasciatvs) seems to be quite as readily able to transmit plague as the oriental insect. How far other fleas are able to transfer infection we have little or no knowledge. But twenty-seven experiments to transmit plague from animal to animal by means of cat-fleas {Cteno- cephalus felis) were once made and none of these were successful. The reason for the failure we do not know. If infected fleas are kept in captivity after they have fed on septicsemic blood, it is found that, after a while, they are no longer able to convey infection. On being dissected no bacilli are found in them. A clearing process, therefore, evidently goes on. If a number of fleas be fed on a septicaemic rat and, subsequently, be kept under observation and nourished on healthy animals, the proportion found to be in- fected steadily diminishes day by day. It is remark- able that the existence of numerous plague bacilli in the stomach of a flea does not seem materially to affect the insect’s life. Fleas, in other words, do not sufler from plague though they can transmit it.