58 ORGANISED FLUIDS. 



in the blood of the frog, they are very much smaller (see 

 Plate II. Jig. 1.) : from whence it would result that the 

 process adopted by nature for the conversion of the white 

 globules into red, would, in the two classes of the animal 

 creation cited, be of a character wholly different the one 

 from the other. In the first-mentioned the transmutation 

 would be a work of decrease j in the second, of increase, or 

 superaddition ; and this supposition, I conceive, would be 

 tantamount to charging nature with the commission of a gross 

 inconsistency. 



There are other observers, again, who believe in the for- 

 mation of the coloured blood corpuscles out of the colourless 

 ones, in a manner totally different from that described by 

 M. Donne. 



Thus Mr. Jones, in a communication recently made to 

 the Royal Society, and entitled " the Blood Corpuscle con- 

 sidered in its different Phases of Development in the Animal 

 Series," states that the blood corpuscle presents throughout the 

 animal kingdom at least two phases of development ; in the 

 first of these the corpuscle is granular, and in the second 

 nucleated: when in the former phase it is denominated 

 " granule blood cell" and in the latter " nucleated Mood cell;" 

 the first condition, or that of granule blood cell, is synony- 

 mous with the colourless corpuscle of the blood. 



But each of these two phases presents likewise two stages 

 in their growth or formation: thus the granule blood cell 

 may be either coarsely granular, or it may be finely granular; 

 and the nucleated blood cell may be either uncoloured or 

 coloured. The first three stages are encountered, according 

 to Mr. Jones, in the whole animal series, but not the fourth 

 stage, the coloured condition of the nucleated blood cell, 

 which is wanting in most of the Invertebrata, and in one of 

 the series of Vertebrate animals, a fish, the Branchiostoma lubri- 

 cum Costa ; in all the other divisions of the animal kingdom 

 it is present, as in the Oviparous Vertebrata and the Mam- 

 malia. 



In the latter class, the Mammalia, a third phase is super- 

 added to the other two, that of a "free codiform nucleus:" 



