132 Royal Society. 



corpuscles. These he distinguishes as the phases, first of the gra- 

 nule blood'Celli which he describes as a cell filled with granules, dis- 

 closing by the solvent action of dilute acetic acid on these granules 

 a vesicular, or as the author terms it, a " cellceform " nucleus. These 

 granule cells appear under two stages of development, namely, the 

 coarsely granulous stage and the finely granulous stage. The se- 

 cond phase is that of the nucleolated blood'Cell, oval in shape, con- 

 taining a vesicular (or " cellaeform ") nucleus, and red-coloured mat- 

 ter. These cells likewise appear under two stages of development ; 

 colourless in the first and coloured in the second, in which last stage 

 it constitutes the red corpuscle. In the early mammiferous embryo, 

 he finds, in addition to the former, a third phase, that of/ree vesicu- 

 lar nucleus, exhibiting, like the nucleolated cell, the colourless and 

 the coloured stages. 



On examining the corpuscles of the lymph of vertebrate animals, 

 the author finds them in all the classes to be identical in structure 

 with their blood-corpuscles, and differing only in the inferior degree 

 of coloration attending their last stage. In the oviparous classes, he 

 observes that the nucleolated are more numerous than the granule 

 cells, while in the mammifera the latter are predominant, which is 

 the reverse of the proportion in which they exist in the blood of 

 these animals. He finds that some of the nucleolated cells of the 

 contents of the thoracic duct exhibit a marked degree of coloration, 

 and have an oval shape ; thus offering a resemblance with the blood 

 of the early embryonic state. 



The blood- corpuscles of all the invertebrate animals in which the 

 author examined them, present the same phases of granule and nu- 

 cleolated cells as in the higher classes, excepting that in the last 

 stage of the latter phase the coloration is very slight, but the vesi- 

 cular nucleus is frequently distinctly coloured. As in the higher 

 classes, corpuscles exist in different states of transition from the gra- 

 nular to the nucleolated form of cell. In some of the invertebrata, 

 corpuscles are found which appear to be the nuclei of some of the 

 nucleolated cells become free ; and these the author considers to be 

 abortions, rather than examples, of cells having attained their third 

 phase of free cells. Corpuscles are also met with in these animals, 

 in greater or less abundance, belonging to the lowest forms of or- 

 ganic elements, namely, elementary granules. 



The comparison which the author institutes between the blood- 

 corpuscles of the vertebrate and invertebrate divisions of the animal 

 kingdom, tends to show that they in all cases pass through similar 

 phases of development, except with respect to the last, or coloured 

 stage of the nucleolated cell, which they do not attain in the lower 

 classes of animals. He finds that the blood-corpuscles of the crab, 

 according to an analysis made by Professor Graham, contain a sen- 

 sible quantity of iron, perhaps as much as red corpuscles. He con- 

 siders the corpuscles of the blood of the invertebrata, inasfar as re- 

 lates to the absence of nucleolated cells, as resembling those of the 

 lymph of vertebrate animals. 



" Observations on the Growth and Development of the Epider- 



