CORRESPONDENCE                                        401

possibly biting flies or other insects may play a part. The conditions under which
contact experiments are carried out, namely, in bare enclosures or in sheds, may
not be favourable for the presence in numbers of biting flies. These are generally
most numerous on swampy grazing grounds such as the bed of a tank, at watering
places, or in the neighbourhood of mud wallows. It would be of interest to know
if the larger biting flies were numerous at the time Mr. Cooper's experiments were
carried out, and if not, would the same experiment give different results if carried
out at a time when the larger biting flies were numerous ?

I notice that Capt. Datta in his article in the same Journal dismisses insect
vectors as of no importante in the transmission of rinderpest, to my mind on
rather insufficient evidence. He cites leeches, ticks, mosquitoes, house flies and lice,
but beyond stating that Curasson had negative results with a fly (Tabanus) he does
not seem to have given much consideration to the possibilities of Stomoxys and
Tabanus. If Glossina can transmit infection, as Hornby thinks, I should imagine
that the much larger and deeper biting Tabanus and Stomoxys could do so too.

                                                                                                 Yours faithfully,
                                                                                              W. CRAWFORD,
                                                                Government Veterinary Surgeon, Ceylon.

Dated 18th February 1933.