1880.] 



MICROSCOPICAL JOURNAL. 



211 



on physiology it is expressly stated 

 that tney do not have one. The 

 peculiarity and persistence of the 

 form of these corpuscles, their 

 behavior on the application of pres- 

 sure, and the presence of one line 

 only to distinguish the difference in 

 density of the contents of the cell 

 and its surrounding medium, when 

 two should exist— namely one to 

 denote the difference in density or 

 degree of refraction of the cell 

 contents and its wall, and a second 

 to show a like difference between 

 the cell-wall and its surrounding 

 medium, whatever that may be — 

 are certainly in favor of the latter 

 view. Investigations of Dr. Jos. 

 G. Richardson seem to go to con- 

 tradict this view and to hold to 

 the old. 



" The conclusions reached by him 

 were based upon observations on 

 human corpuscles, and on those of 

 the menobranchus or proteus. Ob- 

 jective used, -gV inch. He states 

 and clearly proves the corpuscle to 

 be composed of " hsemato-crystallin 

 freely soluble in water," and a se- 

 cond substance, " whitish in hue 

 and insoluble in water." But when 

 he considers this latter as consti- 

 tuting a cell-wall, it is then that we 

 cannot but differ from him. ■^' * * 



"•The criticism of Dr. Richard- 

 son's deductions, ably stated by a 

 reviewer, lies in this : 'that because 

 these phenomena are compatible 

 with the supposition that there is a 

 cell-wall to the corpuscle, he thinks 

 they cannot be compatible with any 

 other view.' * * * 



" Indeed, the explanation of Rol- 

 lettof the structure of the corpuscles 

 is most consistent with the obser- 

 vations of microscopists. He con- 

 siders the corpuscle as formed of 

 " oikoid " (analogous to stroma), 

 which takes up the hsemato-crystal- 

 lin in solution — but that there 

 is no cell-wall. That something — 



aame it ' stroma, ' ' oikod,' ' shell,' 

 which you please — does remain 

 when the coloring matter is dissolv- 

 ed out, no one can deny. This is 

 better named structureless, jelly- 

 like " frame-work," which it may, 

 but to us undoubtedly is, though 

 Dr. Richardson considers it to be 

 the cell-wall. * * * 



"The question now naturally 

 arises, that if these morphological 

 constituents of the blood have elicit- 

 ed so much study and controversy, so 

 much investigation , and withal are 

 so important in the economy, what 

 is their origin, their mode of deve- 

 lopment, of evolution? What is 

 their relation to one another ? What 

 bearing do they have on other or- 

 gans of the body, and what is their 

 signiiicance in pathological pro- 

 cesses and morbid conditions ? In 

 all vertebrates, two sets of cor- 

 puscles are developed at different 

 periods of life: a first set exists 

 until the lymph and chyle-corpuscles 

 appear; a second, which are devel- 

 oped from the last two. The former 

 are simply the embryonic red cor- 

 puscles. l!Tow, in order to compre- 

 hend the origin of these cells in the 

 embryo, we may first state the 

 outlines of embryology. By the 

 procass of segmentation the blasto- 

 derm is formed which represents 

 the germ of the future being. Its 

 two or three layers each give rise 

 to distinct tissues and parts of the 

 body. They are the epiblast, the 

 mesoblast, and hypoblast. The me- 

 soblast, with which we are concerned 

 gives origin to the connective-tissue 

 group, the muscles, lymphatic and 

 vascular systems, and their acces- 

 sories — hence the blood. The cor- 

 puscles and vessels are formed in 

 the germinal area, the area vascu- 

 losa. These, termed ' embryonic 

 red corpuscles,' are plain, spherical 

 masses of protoplasm, containing a 

 nucleus.They are slightly larger than 



