192 DR. s. H. LONG ON THE MOSQUITO-MALARIA THEORY. 
with which the insect inflicts its bites. He further completed the 
biological cycle of evidence by demonstrating that healthy Sparrows 
could be infected with the Proteosoma by the bites of hand-reared 
Mosquitoes previously fed on infected birds. These researches have 
since been confirmed, both in general bearing and in detail, by the 
observation of the fertilisation process in the case of halteridium of 
birds ( ffaemamoeba danilewslrii), as well as of human aestivo- 
autumnal parasites ( Haemomenas prciecox). 
I might here remark, by the way, that besides man, certain 
Batrachia and Reptiles are known to suffer from Malaria, and the 
endoglobular form of the parasite in the edible Frog ( Rana 
esculenta) has been worked out, though what the definitive host is 
in this case it is not yet known. Many birds similarly suffer from 
the disease, and in the case of the Pigeon ( Columba Uvia), the 
Lark ( Alauda arvensis), and the Little Owl ( Athene nodua), the 
parasite has been identified. In mammals, Malaria is known in 
Oxen, Calves, Sheep, Lambs, Dogs, and probably in Horses also. 
Bovine Malaria has long been noticed in certain districts where 
human Malaria exists, and that it attacks preferably imported breeds. 
Smith and Kilborne have demonstrated that the parasite is trans- 
mitted to Oxen by the bite of a special tick, the Ripiceplialus 
annulatus, about the size of a pin’s head. After sucking the Ox’s 
blood the tick falls off engorged and subsequently lays an egg, and 
the daughter ticks are capable of again transmitting the disease. 
These ticks are constantly found in districts where bovine malaria 
prevails. 
Having said this much, most of you will, I expect, be convinced 
of the truth of this Mosquito-Malaria Theory, but in case any should 
still remain unbelieving, I will quote two experiments which in 
themselves should be convincing. 
Speaking last year of how to impress upon the English public 
the importance of the Mosquito-Malaria Theory, Dr. Manson said : 
“ As the histological, biological, and experimental evidence which 
had satisfied men of science was not understood by the public, it 
seemed to me that some simple demonstration was required such as 
would be unanswerable, and at the same time readily comprehended 
by laymen.” Two Italian investigators, Grassi and Bignami, had 
already proved Malaria to be conveyed by the Mosquito, but their 
experiments, although undertaken with every possible precaution, 
