THE BLOOD-COKPUSCLES OF THE ANNELIDES. 495 



taken to exclude the possibility of any intermixture of perivisceral 

 fluid, the smaller was the number of any other elements in a 

 microscopic slide of the red fluid of the worm, I, after some de- 

 liberation with myself and others, decided to speak (p. 124) of this 

 fluid as being ' non-corpusculated.' Similarly Dr. A. Rollett, 

 the author of the article ' Blood ' in Strieker's ' Handbook/ had said 

 (' Sitzungsb. Akad. Wiss. Wien.' Bd. xliv. 2, 3861, p. 630) of a 

 drop of the worm's red fluid that he never found anything like 

 a red corpuscle in it. The real history of these bodies may be 

 given by saying that they are due to the breaking up of true 

 blood-corpuscles, by a process which brings to an end the inter- 

 penetration of their 'zooids' and 'oecoids;' in other words, their 

 genesis is as artificial as that of the similarly minute ' Zimmer- 

 mannsche Korperchen ' in human blood. The way in which I have 

 been led to see this is as follows : — Mr. W. Hatchett Jackson, 

 Demonstrator in the Oxford University Museum, suggested to me 

 that instead of discharging the red fluid from a capillary pipette 

 on to a slide, and so examining it as Dr. Davy and I had done in 

 days before immersion lenses were known in England at least, 

 we should examine it whilst still contained in the pipette and 

 under Hartnack's immersion 10, coagulation occurring very im- 

 perfectly, as Professor Schafer has shown it to do, with frog's blood 

 similarly treated. The red fluid of the worm can thus be seen to 

 possess many true corpuscles, of various sizes, some with homo- 

 geneous, some with granular contents, and some with one or more 

 of the solid coloured bodies mentioned above placed either intra- 

 or extra-globularly. The pipette also draws out of the vessels 

 masses of coherent cells, which in their shape and in the variability 

 of their size resemble many of the free cells, but which always have 

 their contents homogeneous. These masses, like the closely similar 

 aggregations figured by Kupffer (' Zeitsch. Wiss. Zool. 5 xiv. Taf. 

 xxix. fig. 3, «, b, and c\ are, no doubt, the product of the proli- 

 feration of the blood- vascular endothelium. If the pipette has been 

 cleanly plunged into the vessels, it will not be found to contain 

 any of the large amoebiform or other corpuscles which some authors 

 have ascribed to the blood of the worm. If the red fluid is pur- 

 posely or accidentally mixed with water, the appearance described 

 by Dr. Davy takes the place of appearances such as Claparede 

 has figured ('Annelides Chetopodes du Golfe de Naples,' pi. xxvi. 



