PAUASITES Fr.EE DUIIING THEIR WilOLE LIFE. 127 



fclie fall-grown insects bring them, whereas the larvae of 

 gnats get their own living; the mother flea sucks for 

 herself first, and then divides the spoil with her larvae 

 which as yet have no feet. For a long time it was 

 thought that the fleas of different animals belonged only 

 to a single species, and consequently that the flea oi 

 man was not different from that of a cat or a dog. 



Daniel Scholten, of Amsterdam, in 1815, showed by 

 his microscopical observations, that fleas differ from 

 each other ; and in 1832, Duges of Montpellier, investi- 

 gated the distinctive marks of the various species. The 

 observations of Scholten may be found in *'Les 

 Materiaux pour une faune de la Neerlande," by K. T. 

 Maitland. 



The ordinary flea is called Pulex irritans, and espe- 

 cially attacks man in Europe and in North America ; it 

 may be called a fly without wings, and, together with its 

 congeners, it forms a distinct family under the name of 

 PiilicideB, Van Helmont treated of these insects, and 

 gave directions for making them, just as though he were 

 describing a recipe for pomade. At that time, natural- 

 ists supposed that certain fish could be formed spontane- 

 ously, and that nothing but fermentation was necessary 

 in order to bring forth a crowd of living creatures from 

 this molecular disaggregation. Fleas may, perhaj^s, 

 some day find a place in the chemist's shop as well 

 as leeches. We see no reason why homoeopathic 

 bleedings should not be resorted to, as well as homoe- 

 opathic medicines ; we should certainly have more 

 confidence in the effects of the bites of fleas, than in 

 the ef&cacy of remedies subdivided into the millionth 

 part of a grain. 



