REPORT OF THE MALARIA EXPEDITION. 
35 
very rare case of complete solitaries, attacks of fever may perhaps often be attributed to relapses 
due to a long previous infection acquired in the haunts of men. 
Travellers and sportsmen sometimes attribute their fever to having passed througii a 
particular uninhabited but " deadly " spot. Sucli cases are generally questionable. On enquiry 
it is often found that the fever has commenced the very day, or the day after, the traveller has 
arrived at the place he refers to ; so that the necessary phenomenon of an incubation period is 
wanting ! A case is on record where a family of healthy natives were found living in one of tiie 
" deadliest spots " in India [25] ; and we were; informed that some persons who escaped from the 
Benin massacre, and lived several days in the reputedly deadly jungles, escaped without fever. 
It is certainly often possible to explain outbreaks of fever, attributed to such localities, by previous 
infection acquired by the suffering party in rest-houses and Jiative villages en route. 
If a healthy person could be carried to an 'uninhabited but reputedly "malarious" spot in 
a balloon, and should then acquire tiie disease, we should be forced to admit the possibility of 
infection in such places. Failing this, it is at least open to doubt whether autochthonous malaria 
does in fact exist in uninhabited localities at all. 
Even assuming it does so, however, the fact would be explicable without tlie assistance of 
another life-cycle of the parasites, on the ground that Anopheles may possibly convey the infection 
from wild animals \^paragraph 23']. For instance, both monkeys and bats arc often found in 
large numbers in forests reputed to be malarious. 
Failing even this, if it can be shown that autochthonous malaria does exist in uninhabited 
places, the fact would be more readily explained on the liypothesis that the Hajmamoebida; can 
pass from gnat to gnat, than on any other. And this leads to the second question given above. 
Is there any evidence to be drawn from our knowledge regarding the parasites themselves in 
favour of the view that they possess another life-cycle ? 
The Indian observations sliowed that in many of tlie zygotes of H. relkta found in 
C. fatigans, certain large, black, sausage-shaped bodies occurred. These were provisionally called 
by one of us " black spores." They occurred not only in the z)'gotes, but in other parts of the 
gnat ; facts which he at first explained on the assumption that they are produced within the 
zygotes, are liberated on the rupture of these, and are then distributed by the insect's circulation 
throughout its tissues in a maimer similar to the way in which the blasts are distributed. Later, 
however, he observed in gnats which were not infected with Haemamoebidae at all, bodies which 
were very similar to these black spores, but which showed evidences of fission in the manner of 
the fission fungi, and indeed of growth entirely independent of the Haemamoebidae. Consequenth- 
he at once modified his statements about these bodies [21], and suggested that, though he 
could not say for certain what they are, they may be some parasitic organisms in gnats which 
have the power also of invading the zygotes of the Haemamoebidae. He at first thought that they 
might be meant for infecting the larvae of gnats, and indeed made some negative experiments in 
this connection, but later abandoned all hypothesis on the subject pending further researches. 
Since then tlie "black spores" have been found by other observers, who also have tailed in 
elucidatini>; their nature. In Freetown we noted bodies ver\' like them in a few Anopheles ; but 
