420 



SCIENCE. 



[Vol. I., No. 15. 



term, in the blood and urine of persons afflict- 

 ed with chj'luria. The mature form was first 

 described hy Cobbold as Filaria Bancrofti, 

 in 1877 {London lancet, Oct. 6, 1877). As 

 found in the lymph, the parent Filaria emits 

 her 3'oung iu the lymph-stream. The .young 

 Filaria is an elongate, transparent, very active 

 creature, measuring -gig-" x -g-jVo"- I* makes its 

 wajr from the lymph to the blood, where, how- 

 ever, it seems to undergo no growth or de- 

 velopment. In this its new-born state it is 

 enclosed in a delicate, transparent, and rather 

 loose tunic or cyst, and is found in the blood 

 of patients affected "with elephantiasis, but 

 onlj' daring the night. This disease is mani- 

 fest in a thick, livid, tuberculate, and insensi- 

 ble condition of the skin, akin to leprosy. It 

 is endemic over the more thickly populated 

 and tropical portions of the globe, and, in its 

 various forms, is very painful, resulting in de- 

 formity, and not infrequently- in death. The 

 best authorities now believe that various dis- 

 eases of the lymphatic vessels and glands — 

 as varicose groin glands, lymph scrotum, ele- 

 phantiasis, and chj'luria — are pathologicallj' 

 one and the same, and are due to the presence 

 of this Filaria, which has, in fact, been record- 

 ed from South Europe, Asia, Australia, and 

 Brazil ; Dr. Araujo having verified at Bahia 

 its occurrence in the mosquito, and otherwise 

 confirmed the observations of Manson and 

 others in difl'erent parts of the world. 



Before the young Filariae can undergo their 

 full development, tbej' must first enter the 

 hoAx of the female mosquito (Culex mosquito) , 

 ■ whicli sucks them up in her nocturnal attacks. 

 Within the mosquito thej- develop in from five 

 to six da^'s, and upon the death of their host, 

 or before, pass into water frequented by tlie 

 mosquito for purposes of oviposition, and are 

 thus returned, b_y drinking, to the human 

 stomach, from which thej' make their way into 

 some Ij'mphatic vessel, where, the sexes meet- 

 ing, the female remains, perhaps, for years, 

 giving birth to active young. 



In the Customs medical report for the half- 

 year ending March 31, 1882, lately published, 

 and but recently received in this couutrj'. Dr. 

 Manson gives the results of some later obser- 

 vations which are full of interest. It seems 

 that the periodicity in the Filaria disease has 

 no connection cither with temperature, atmos- 

 pheric pressure, or light, but must be looked 

 upon as an adaptation of the habits of the 

 parasite to those of the mosquito. The con- 

 ditions for the ingress of the Filariae into the 

 circulation appear to.be developed ordinarily 

 during the last few hours of the waking state, 



and the parasites are eliminated during the 

 last few hours of sleep. Under ordinary con- 

 ditions of sleeping or waking, the embryos 

 enter the circulation every evening, increase 

 until midnight, and diminish as morning ap- 

 proaches, until they entirely disappear, and 

 are not found from nine a.m. to six p.m. This 

 periodicitj' of the parasite is independent of 

 parturition in the parent, as reproduction is 

 continued during the twenty-four hours. 



The importance of thus tracing to their true 

 source diseases whose origin has long been 

 involved in mj'sterj' cannot be overestimated ; 

 and these facts would seem to give additional 

 reasons for the filtering of drinking-water, and 

 the use of mosquito-bars, in all tropical coun- 

 tries. Dr. Manson suggests that the facts 

 ascertained in this connection may lead to a 

 possible future explanation of the diurnal in- 

 termission and remission of fevers of the ague 

 class. The most interesting conclusions that 

 have been forced upon Dr. Manson are, that 

 the presence of the parasite in the human 

 body does not always or necessarily produce 

 disease ; and that, when disease is produced, 

 it is by exceptional oviparous reproduction 

 instead of the ordinary viviparous mode. 



We give his conclusions in his own words: — 



"In the instances in whicli the parent worm has 

 been discovered, she was found in lymphatic vessels 

 on the distal side of the glands. This has been shown 

 to be in many if not in all cases her normal habitat. 

 Her progeny, therefore, mnst travel along the affer- 

 ent vessels, through the glands, and so on to the 

 thoracic duct, and thence into the blood. The long, 

 sinuous, and powerful body of the embryo is well 

 adapted to perform this journey. But suppose, instead 

 of this mature embryo, an ovum is launched into the 

 lymph-stream i^rematurely, and before the contained . 

 embryo has sufficiently extended its chorion, then 

 this passive ovum must certainly be arrested at the 

 first lymphatic gland to which it is carried by the 

 advancing lymph-current. It measures -;-JriT"X'in", 

 whereas tlie outstretched embryo is only about uii'ito" 

 in diameter. It is much too large to pass the glands; 

 and the embryo, rolled up in its chorional envelope, 

 cannot aid itself. It becomes, in fact, an embolus. 

 Now, Filariae are prodigiously prolific. Myriads of 

 young are expelled in a very short time. I have 

 watched the process of parturition in the minute 

 Filaria corvi torquati. Every few seconds a peristaltic 

 contraction, beginning low down in the uterine horns, 

 and extending to the vagina, expels some twenty or 

 thirty embryos. If this process of partiu'ition occurs 

 prematurely, or peristalsis is too vigorous, and ex- 

 tends to a point high up in the uterine horns, where 

 the embryo has not yet completely stretched its cho- 

 rional envelope, then ova are expelled. These, as 

 they reach tlie glands, where the afferent lymphatic 

 breaks up into fine capillary vessels, act as emboli, 

 and plug up the lymph-channels, one after another, 

 until the fluid that carries them can no longer pass. 

 In this way the gland or glands directly connected 

 with the lymphatic in which the aborting female is 

 lodged are thoroughly obstructed. Anastomoses for 



