60 OBSERVATIONS ON FILARI.E. 



Brazil, Dr. Silva Aranjo found the adult worm on the 16th of 

 October, 1877, and shortly afterwards Dr. F. dos Santos made a 

 similar verification (12th November, 1877). This closes the record 

 of the first two epochs of filarial discovery. A third epoch of dis- 

 covery was opened up when, writing from Amoy, in November, 

 1877, Dr. Manson informed me that he had discovered Filarice in 

 the stomach of mosquitos that had gorged themselves with human 

 blood. Dr. Bancroft, indeed, writing in the spring of the same 

 year, had remarked to me that he fully expected that the haematozoa 

 would be thus transferred, but his examinations of mosquitos up to 

 the time of Manson's discovery had not been successful. Other 

 discoveries and verifications rapidly followed, especially those having 

 reference to the power of the hsematozoa in the production of 

 disease. On this aspect of the subject I cannot now dwell further 

 than to say that the purely clinical questions have already been 

 pretty fully discussed by myself in a paper communicated to the 

 London Medical Society, and published in their recently issued 

 *' Proceedings " (Vol. iv, 1877-79, pp. 129-131). 



I may add that all the various disorders produced by the Filarice 

 in question have been, as it were, rolled together into one by Dr. 

 Bourel-Ronciere, who calls the collective disease Wncherer^s hehnin' 

 thiasis. Others have called the disorders Filariasis, but, obviously, 

 this vague and too comprehensive sort of nomenclature cannot be 

 allowed to stand. It is now tolerably certain that at least a dozen 

 more or less distinct diseases are caused by the larval Filarice, and 

 amongst these are to be reckoned endemic ha^maturia, chyluria, 

 varix, lymph scrotum, elephantiasis, lymphatic growths (helmin- 

 thoma elastica), many other lymphoid afi*ections, a skin disease 

 termed Craw-craw {Filariasis dermathemica), jDrobably leprosy, and 

 perhaps also certain malarial fevers. 



In the acquisition of these results — results which, of course, are 

 not generally accepted, and whose full value and significance will 

 probably not be realised for many decades or centuries to come — the 

 justifiable method of human experiment has played a most con- 

 spicuous part. Initiated by Dr. Manson himself, he was thus enabled 

 to trace out the higher larval stages of growth, after the ha3matozoa 

 had passed from man to mosquito. Having caused an infected 

 Chinese to sleep in a mosquito house, the insects were found gorged 

 with blood the next morning. On examining the contents of their 

 stomachs, Dr. Manson ascertained that a relatively far greater pro- 



