ELEPHANTIASIS 89 



The proportion with signs of lymphatic obstruction 

 were : Portuguese, 13 ; Negro, 7*4 ; Indian, 0*9. 



Even as regards the two sexes the same held good. 

 In British Guiana, amongst the Negroes, 24 per cent, of 

 the females harbour filariae and 13 per cent, of the men. 

 Elephantiasis occurs in the females 15 per cent., as against 

 7*4 per cent, in the males (vide chart, fig. 41). 



The opposition to the view that the F. bancrojti is 

 responsible for the prevalence of elephantiasis lymphatic 

 obstruction is due to the fact that in the majority of 

 cases of elephantiasis no filarial embryos are found in the 

 blood. This was noted nearly thirty years ago and has 

 been confirmed repeatedly. It is certain -that in any 

 country where filariae are common the proportion of 

 persons harbouring these parasites is smaller in those 

 with elephantiasis than amongst those perfectly healthy. 



In some cases, though the filarial embryos are not 

 found in the blood they may be found in the lymph from 

 the elephantoid part, but these cases are rare. In other 

 cases, though no filariae are present in the blood, there 

 may be a history of previous undoubted filarial manifesta- 

 tions such as chyluria or lymph scrotum. Bahr, and 

 others subsequently, have shown that there may be 

 sexually mature living filariae in the glands and none of 

 the embryos have passed into the blood. 



Those who support the proposition that F. bancrofti is 

 responsible for the prevalence of elephantiasis lymphatic 

 obstruction urge that the absence of filaria from the 

 blood in these old-standing cases of lymph obstruction 

 might be expected. 



The adult causes the obstruction, but in so doing shuts 

 off the lymph in a given area from the general circula- 

 tion and the embryos therefore cannot get into the blood. 

 Further, the obstruction once formed is persistent, whilst 

 the filaria that caused the obstruction will die, and it is 

 even suggested that the obstruction is caused in many 

 instances by dying or dead filariae. 



Before considering these views it is well to take into 

 account the clinical history of cases of elephantiasis. 



