366 



PROr. T. S. COBBOLD ON THE 



instances they refer to the time of publication. I can hardly 

 suppose, notwithstanding the pains I have taken, that it is alto- 

 gether free from error. Be that as it may, the leading features 

 of the record must, I think, be allowed to pass unchallenged ; and 

 if so, the following six propositions will likewise be accepted as 

 correct : — 



1. Filar ia hancrofti is the sexually mature state of certain 

 microscopic worms hitherto obtained either directly or indirectly 

 from human blood. 



2. The minute hsematozoa in question, hitherto described as 

 "Wucherer's Filarice, Filaria sanguinis hominis, Trichina cystica, 

 Filariose dermathemica, and so forth, are frequently associated 

 with the presence of certain more or less well-marked diseases of 

 warm climates. 



3. The diseases referred to include chyluria, intertropical 

 endemic hsematuria, varix, elephantiasis, lymph-scrotum, and 

 lymphoid affections generally, a growth called helminthoma elastica, 

 a cutaneous disorder called craw-craw, and also, not improbably, 

 leprosy itself. 



4. It is extremely probable that a large proportion or, at least, 

 that certain varieties of these affections are due to morbid 

 changes exclusively resulting from the presence of Filaria han- 

 crofti or its progeny within the human body. 



5. It is certain that the microscopic hsematozoa maybe readily 

 transferred to the stomach of blood-sucking insects, and it has 

 been further demonstrated that the digestive organs of the mos- 

 quito form a suitable territory for the further growth and meta- 

 morphosis of the larval Filarice. 



6. The character of the changes undergone by the microscopic 

 FilaricB, and the ultimate form assumed by the larvse whilst still 

 within the body of the intermediate host {Culex mosquito), are 

 amply sufficient to establish the genetic relationship as between 

 the embryonal Filaria sanguinis hominis, the stomachal Filarice of 

 the mosquito, and the sexually mature Filaria hancrofti. 



rinally, it remains for me to glance at the practical conse- 

 quences that may be expected to flow from the acceptance of 

 these conclusions. 



One of the greatest hindrances to the due recognition of the 

 remarkable part played by parasites in the production of human 

 endemics and animal epizootics arises from the circumstance that 

 no inconsiderable number of minute worms may infest a host 



