OBSERVATIONS ON FILARIJE. 61 



portion of the Film-ice existed in a drop of the sucked blood than 

 in a drop taken from the Chinese in a direct manner. Thus, it was 

 not unnaturally inferred that the construction of the proboscis was 

 in some way or other expressly fitted for drawing the worm out of 

 the capillary blood vessels. Dr. Manson examined the gorged 

 insects at regular intervals of time, and he forwarded to me the 

 details that were subsequently communicated to the Linnean 

 Society, and published in their Journal (1879). He likewise 

 reported the results in the Custom's Gazette ; but probably the 

 summary which I have given in my recently issued work, with 

 illustrations reduced from Dr. Mansoh's original figures, sufficiently 

 explains all that need be known on this part of the question. 

 Thus the position stood at the commencement of last year ; and the 

 novel facts and deductions to which I now invite your attention, 

 must be regarded as a continuation of those records. I may add 

 that since the issue of my treatise, Dr. Lewis has published a 

 beautifully illustrated memoir in which he not only verifies a great 

 deal of what Dr. Manson had already observed, but also adds a multi- 

 tude of interesting details. Dr. Lewis's writings, however, do not 

 in any sense anticipate the data now brought forward. In the 

 present communication. Dr. Manson commences by referring to the 

 mosquitos (which I have now the pleasure to show the Club) and 

 to a Chinese scrotum at present in my possession. He gives par- 

 ticulars of the remarkable case to which the scrotal preparation 

 refers. He points to a newly observed fact that the worms enter 

 the blood periodically. He interprets the significance of this law 

 of periodicity in some of its more obvious bearings. He appears to 

 have discovered the special means by which the insects contrive to 

 fish up, as it were, the haematozoa. He explains the immediate 

 consequences of this curious phenomenon. I may add, parentheti- 

 cally, that this process affords a remarkable instance of so-called 

 free parasitic ectozoa stealing true entozoa and taking them as 

 prisoners from human hosts, to lodge them, as transported guests, 

 in their own interior. The matter does not stop here. Dr. Manson 

 explains how it happens that human blood does not contain FUaricB 

 during the afternoon. He gives a tabular record of the results of 

 the daily examination of the blood at different hours. He shows 

 how the embryos, with almost military punctuality, march to their 

 nocturnal quarters. Proofs of this extraordinary behaviour are 

 supplied by repeated observations. He hints at the importance of 



