Mr. H. J. Carter on Microscopic Filaridse. Ill 



prevailed in " the months of March, April, May, and June, the 

 cases which occurred in these four months constituting three- 

 fourths of the entire number throughout the year/' The maxi- 

 mum was in May, viz. 125, and in June, ] 02 cases ; and the 

 minimum in January, viz. 11 cases, after which there is a rapid 

 increase to May ; so that it is towards the end of the dry weather 

 and beginning of the '^rains'' — that is, towards the end of 

 spring and the beginning of summer — that Dracunculus is most 

 prevalent. 



How this can be brought to bear upon the time required for 

 the full development of Filaria Medinensis I am unable to state. 

 According to my observations, Urolahes palustris ceases to lay 

 by the beginning of May, and commences to breed as early as 

 January : after May, and on to August, all the females that I 

 have met with, although robust, have presented a shrunken 

 state of the generative organs, and have been without ova. If, 

 then, we assume that all the other species follow this type, and 

 that it is a Urolabes which passes into the human body and be- 

 comes transformed into Filaria Medinensis, then the time re- 

 quired for the development of the latter would be very short. 

 But then there are a number of species, perhaps, which only 

 come into active life and breed during the '^ rains '' — at least, I 

 have never met with them at any other period ; and if it be one 

 of these, either in an embryonic or full-grown state, which enters 

 the body, then the time for their development into F. Medinensis, 

 as they can only enter during the '^ rains," must be at least ten 

 months ; while there are well- authenticated cases where sailors 

 have gone to England from Bombay, and on returning to it 

 after about a year, have had Dracunculus just before they arrived 

 at Bombay : but these cases, unless it could be shown that the 

 individual had had no contact with water from a tropical region 

 from the time he left it until his return, prove nothing. 



Lastly, some localities are more productive of Dracunculus 

 than others, and the country or the suburbs of a town more than 

 the town itself. Thus, in the least-populated part of the island 

 of Bombay, where the Artillery were formerly cantoned, Dra- 

 cunculus prevailed so much, both among the men and officers, 

 that the place had to be abandoned, and the Artillery brought 

 back to barracks in the town, — an occurrence which, if Filaria 

 Medinensis arise from one of the Urolabes, seems to derive ex- 

 planation from the fact to which I have before alluded, viz. that 

 the microscopic Filaridse abound most in water where there 

 is an abundance of Algae and aquatic plants, and that this is 

 more likely to be the case about uncultivated ground, and in 

 tanks formed chiefly out of natural depressions in the soil, than 

 in a town where there is neither one nor the other. 



