( 229 ) 

 KECOED 



OP CURRENT RESEARCHES RELATING TO 



INVEETEBRATA, CEYPTOGAMIA, MICROSCOPY, &c.* 



ZOOLOGY. 



A. GENERAL, including Embryology and Histology 

 of the Vertebrata. 



Norris's Third Corpuscular Element in Blood. t — Dr. Norris has 

 recently propounded a new view as to the histology and growth of 

 blood-corpuscles, concluding that in normal mammalian blood there 

 are a large number of colourless, invisible, biconcave disks similar in 

 every respect except colour to the red corpuscles, and that they are in 

 fact an earlier stage of the latter, in which they have not yet obtained 

 haemoglobin. 



Dr. Norris first suspected the existence of these corpuscles whilst 

 studying microphotography, when he observed that exceedingly faint 

 outlines of coriiuscles were represented on the photographic plate, 

 which could not be discovered in the original preparations. On 

 further examination he also observed that in very thin layers of fresh 

 blood the red corpuscles were often seen to impinge upon some in- 

 visible body similar in form to themselves, which body might not 

 unfrequently be observed to make an indentation in the jjlastic stroma 

 of the red corpuscle. Dr. Norris was led by these appearances to 

 infer that there existed in the blood bodies which are invisible to the 

 eye by reason of possessing the same refractive index as the liquor 

 sanguinis in which they are immersed. He concluded, therefore, 

 that if the serum could be withdrawn they would be rendered visible. 



With this object he designed two very ingenious methods of with- 

 drawing the serum. One process, which he calls " packing," consists 

 in taking a slightly convex cover-glass, and strapping it by means of 

 strips of adhesive plaster to a microscopic slide. When so arranged 

 Newton's rings should be produced across the centre of tlie cover-glass, 

 the surfaces being tlien s(!2)aruted by a space not greater than yo^ j^- 

 of an inch. If a drop of blood be placed at one edge of the cover- 

 glass it will i)euctrate by tlio force of capillarity, but the glass surfaces 

 are in such close contact that the corpuscles can only enter flatways 

 and in single layer. At the spot whero the rings are formed the 

 space is too narrow to allow tho corpuscles to pass; they therefore 



* I^T It should 111! undtT.stood lliat tlie Sociity iln not liold tlicmselves respon- 

 sible for the views of the authors of the papers, Ac, reftrred to, nor for the manner 

 in which those views may lie expressed, the ohji-ct of tlie Keeord Unnt^ to pri'sent 

 a summ:iry of tlie piipcTs us wtwilh) }iuhlislicd. Ohjictinns and corrections should 

 thereliire, for llic must part, he addrcsst-d to tlic auliiors. 



f 'On the ()ri.i,'in and Mode of Divtlnpnunl of tiie Morplmlogical I'dements 

 of Mammalian I{lood,'l)yUieliard Norris, M.D., I'rof. ofPhysiulopy, — Birmiiipliam, 

 1S7'J; ahatract by Mrs. Kriiest Hart in ' London Medical Record,' Jan. 15, 1880. 



