170 THE HOUSE FLY—DISEASE CARRIER 
tigator found that flies bore living gonococci upon their 
feet three hours after they had been soiled with secre¬ 
tion, since they infected sterilized plates with which 
they came in contact. 
Nuttall and Jepson conclude their consideration of 
ophthalmia with the following statement: “The evi¬ 
dence regarding the spread of Egyptian ophthalmia by 
flies appears to be conclusive, and the possibility of 
gonorrheal secretions being conveyed by flies cannot be 
denied.” 
Diphtheria 
Nuttall and Jepson have been able to find only one 
reference to the dissemination of Bacillus diphthericu 
by flies. They state that Dickinson (1907) cites Smith 
(1898) as having tried the oft-repeated type of experi¬ 
ment of allowing house flies to walk over infected ma¬ 
terial and then over sterile media. A positive result 
was obtained as a matter of course. The authors state 
that there is no evidence that under natural conditions 
flies have anything to do with the spread of diphtheria, 
but indicate that it is of course conceivable that they 
may convey the infection under suitable conditions. 
Small-pox 
The only published account of the possible relation 
of flies to small-pox cited by Nuttall and Jepson is 
taken by them from a paper by Hervieux, read June 5, 
1904, to the Academy of Medicine at Paris, in which 
he states that Laforgue at a locality in the province of 
Constantine observed that during an epidemic of small- 
