NOTES AND MEMOKANDA. 
377 
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 
haematuria, varix elephantiasis, lymph-scrotum, and lymphoid affections 
generally, a growth called Helmintlioma 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 Bancrofti or its 
progeny within the human body. 
5. It is certain that the microscopic haematozoa may be readily 
transferred to the stomach of the blood-sucking insects, and it has 
been further demonstrated that the digestive organs of the mosquito 
form a suitable territory for the further growth and metamorphosis of 
the larval Filar ice. 
6. The character of the changes undergone by the microscopic 
Filarice and the ultimate form assumed by the larvae 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 Bancrofti.'’ 
Dealing with the practical consequences which may be expected to 
flow from a fuller recognition of the importance of this Filaria, the 
author points out that a consideration of the highest value in relation 
to epidemiology generally, and more especially in regard to the practical 
question as to the best methods of stamping out parasitic plagues, is 
that which refers to the life-history of the entozoon itself. It must 
be obvious that in all cases where the intermediate host can be 
captured and destroyed, the life cycle of the parasite can be broken or 
interrupted ; and if thus broken there is an end to the further propa- 
gation of the species. The knowledge that we have acquired by 
experimental research in this direction has already enabled us to set 
a limit upon the prevalence of certain well-known disorders, such as 
trichinosis, cestode tuberculosis, and so forth. In the case of 
epizootics, however, which are not merely dependent uj)on minute 
entozoa, but which are also, in the way that we have seen, indirectly 
due to the action of intermediary hosts that cannot be readily 
captured or destroyed, our power of arresting the disease is compara- 
tively limited. In the case of Filaria Bancrofti it is probably not 
necessary either that a dead or living mosquito should be swallowed 
to ensure infection; but it is necessary that the parasitic larvse should 
have dwelt within the mosquito in order to arrive at the highest stage 
of larval growth prior to their re-entrance within the human territory. 
Undoubtedly the larvae of Filaria Bancrofti are swallowed with potable 
waters. The perfect filtration of these waters before use would 
certainly che. k, and in course of time would probably cause the total 
extinction of several of the many virulent diseases that now afflict the 
inhabitants of warm climates.* 
* ‘Journal of the Linnean Society ’ (Zooh), vol. xiv. p. B.o6. 
VOL. I. 2d 
