1878.] T. R. Lewis — Hsematozoa in Stomach o/Culex Mosquito. 91 



observed to manifest very active movements which may possibly continue 

 for several hours on the slide. If the insect be kept for 24 hours before 

 examination it is probable that the movements of the parasites will be more 

 sluggish, and their form probably altered owing to irregular contractions 

 and dilatations of their substance — changes which may also occasionally be 

 observed when embryo-hsematozoa are preserved on a glass slide, and they 

 may sometimes be kept alive thus, if in suitable media, for two or three 

 daj's. When the insect is not examined till the third day, the contained 

 parasites will probably manifest marked signs of disintegration — and possibly 

 every indication of life will have disappeared from many of the specimens. 

 After the third or fourth day I have not seen any active specimens of these 

 entozoa in the stomach or in any part of the alimentary canal of the mosquito, 

 those which remain have undergone more or less fatty degeneration, are readily 

 stained with eosin, which, as far as my experience goes, is not the case so 

 long as they are alive and active. After the fourth or fifth day it is very 

 rare that traces of any hsematozoa-like objects can be detected at all, so that 

 it must be inferred either that they have succumbed to the digestive action 

 of the insect's stomach,* or been disposed of along with the excreta. It 

 will of course be understood that these remarks refer solely to the results 

 of personal observations which have up to the present time been made in 

 India — it is quite possible that a more extended knowledge of the subject 

 may modify the conclusions which at present it seems natural to draw. In 

 the meantime I cannot say as a result of direct observation that the 

 mosquito serves as the intermediary host to the development of the Mlaria 

 sanguinis -hominis or other nematoid haematozoon. 



It may further be remarked that it would seem that in this country 

 the mosquito obtains its haematozoa in great part from pariah dogs ; 

 the blood of fully one-third of which, as I had occasion to point out a few 

 years ago, is infested with microscopic parasites closely resembling those 

 found in man. 



[Addendum : — A few days after the Meeting an incident occurred 

 which materially aided in elucidating this matter. It was observed that 

 nearly all the mosquitoes captured in one of the servants' houses contained 

 hsematozoa, so that the supply of suitable insects in all the stages of their 

 growth became amply sufficient for all requirements. The result of the 



* Leuckart mentions that a similar result was observed by Fedschenko to follow 

 the ingestion of dracunculus- embryos in the stomach of the Cyclops. The latter is 

 believed to serve as an intermediary host for the development of the Gninea-worm— the 

 embryos, however, gain access to the body of the Cyclops by piercing the cuticle. 

 When the embryos arc swallowed they are digested. 



