THE NEiVIATOID HjEMATOZOA OF MAN. 253 



water invariably yielded negative results in my hands. It would 

 seem that the larvse had perished. As the quantity of water 

 used was so small, it is hardly possible, had lilarise in any stage 

 of growth been present, that they could have so completely 

 escaped observation. Possibly the more or less artificial condi- 

 tions necessarily associated with the conduct of such experiments 

 may account for these negative results. In the meantime I 

 cannot, as a result of personal observation, affirm that a sojourn 

 in the body of the mosquito, and subsequent transference to 

 water, suffice to bring the F'daria sanguinis-Jiominis to maturity. 



A few words may be said regarding other hsematozoic parasites 

 which appear to find their way into the bodies of mosquitoes. 

 In the first place, it may be mentioned that dogs appear to 

 furnish a certain proportion, as I have repeatedly found Filarise 

 in these insects in which not the slightest trace of the envelop- 

 ing cyst, which characterises the human hsematozoon, could be 

 detected. Unfortunately the corpuscles of the dog's blood are 

 so like those of man, as to size and appearance, that it is not 

 possible to distinguish them with certainty, so that the examina- 

 tion of the fluid contents of the mosquito's stomach does not 

 tend to throw any light on the source of the ha^matozoa in this 

 instance. It is probable that other animals also contribute to- 

 wards rendering the diagnosis more difficult. 



EiG. 3 .... X 500 diam. 



Embryos of a nematoid hehninth from a bird, obtained in the stomach of a 

 mosquito. A few blood-corpuscles are included in the sketch. 



It is not uncommon, for example, to find the blood-corpuscles 

 of birds forming a portion of the contents of the mosquito's 

 stomach, and I have on several occasions observed extremely 

 small embryo-nematodes associated with such corpuscles. Some 

 of these are represented in the accompanying woodcut (fig. 3). 

 If these helminths be compared with the figure given of the 



VOL. XIX. NEW SER. R 



