1862.] OP THE BLOOD OP VERTEBRATES. 93 



teresting it is, among the first anatomical fruits of Mr. Lister's very- 

 important labours in the improvement of the microscope, and withal 

 so accurate that it ought at once and for ever to have dispelled any- 

 further belief in this imaginary nucleus of the blood-disc of Man. 

 Yet, after all, it does not appear that their observations were pushed 

 far enough to verify the remarkable exactness of Hewson's descrip- 

 tion regarding the oviparous Vertebrata, but only to show its inac- 

 curacy when applied to Mammalia. And so here we were left to the 

 distraction of half-truths, that fruitful source of error, very pre- 

 cise and conscientious in themselves, but still so confounding two 

 things fundamentally different as to obscure the whole truth. This, 

 indeed, as in so many other cases, lay between both parties ; for the 

 descriptions of Hewson and of Hodgkin and Lister are quite accurate 

 and real, when confined, as they ought always to be, to the class of 

 animal on the blood of which those excellent observers were severally 

 engaged. 



Lastly, in 1842 and 1845 Mr. "Wharton Jones in England, and 

 M. Donne on the Continent, fully coincided with me as to the dif- 

 ference in question between the Mammalia and the lower Vertebrata ; 

 and this essential fact as to the "vexed question of a nucleus" was 

 then established evermore, though in 1 84 1 Dr. Rees and Mr. Lane 

 were still maintaining that there really is a nucleus in the blood-disc 

 of Man. But their supposed nucleus seems to be identical with 

 what I have always depicted and described as the membranous base 

 or frame of the corpuscle, and similar to the part figured by Home 

 and Bauer, but a very different thing from a nucleus. 



Now, if we wash the red corpuscles of Mammalia in water, using 

 a tall narrow jar or even a test-tube, allowing them to subside, de- 

 canting the supernatant liquid, and adding fresh portions of it until 

 all the colouring-matter and viscid part be removed, there will be a 

 whitish precipitate, consisting mostly of pale, thin, nearly trans- 

 parent, flattened circular discs. These are the membranous bases 

 or frames of the corpuscles — corresponding to the globuline.of some 

 authors — quite insoluble in water, and so faint as not to be easily 

 seen until their opacity has been increased by some such reagent as 

 corrosive sublimate, which makes them very distinct. In short, this 

 washed corpuscle is its colourless tegumentary frame, which, thus 

 treated, is finer and smaller than (that is to say, about two-thirds 

 the diameter of) the fresh unwashed corpuscle, thinner and of larger 

 comparative diameter than the nucleus of the blood-disc of oviparous 

 Vertebrata, and approaching in size to, but wanting the globular form 

 of, the objects represented in the beautiful drawings by Bauer : — 



Fig. 1. Outlines of the human corpuscle, the first and second as 

 seen flat and on edge ; and the third showing the thin, delicate, faint 

 and colourless membranous frame or base of the same, and entirely 

 devoid of a nucleus, after three days washing in water. At fig. 12 

 is seen, first, a sketch of a regular corpuscle of a bird, and next, the 

 same corpuscle made round, and clearly showing its nucleus after 

 similar washing in water. This washed Qorpuscle is represented 

 rather larger than it should be. 



