70 



OB8ERVAT10XS ON FILARIJS. 



" When embryos were very few or altogether absent, the examina- 

 tion was made during the afternoon. To show you how punctual 

 tlie embryos are in keeping their time, I had this man brouglit to my 

 house, and had examinations of his blood made every four hours. 

 At the same time I availed myself of the opportunity to feed the 

 mosquitos I have sent you on his blood, making the case as com- 

 plete as possible. 



*' The quantity of blood examined was, as nearly as possible, the 

 same each time — a small drop, or as much as would keep well 

 together on the point of the finger without running off. 



*' One evening I watched the influx of embryos, examining the 

 blood very frequently. At. 4 p.m. I could not find one ; at 6 p.m. 

 I found one, at 7 p.m. two, at 7.30 p.m. ten, at 8 p.m. 29, at 

 9 p.m. 37. 



" As far as I have examined I find that in other cases the 

 embryos observe the same periodicity. I have a gardener who 

 comes from a filarious district. I knew his blood sometimes con- 

 tained worms. It was examined on three occasions during the 

 afternoon without finding embryos. Yesterday evening it was 

 again examined, about 9 o'clock, and was swarming with Filaricp. 

 A neighbour's chair coolie at 4 p.m. had no embryos ; at 9 p.m. he 

 had 28 in one slide, and so on. 



