Further Experiments as to the Potency to Various Disinfectants against Pulex Cheopis

Another reason for repeating my original experiments is, because it has become evident that there is a very large margin of unavoidable error in this method of investigation, and only by a long series of observations by different men can conclusions in any way reliable be obtained. One factor of error for which no correction is possibie, is the great variation in resistance found in individual fleas, quite apart from the fact that large females are generally more resistant than small males. In consequence of this, although the results of most experiments are regularly progressive, it happens ever)