230 RECORD OF CURRENT RESEARCHES RELATING TO 



become "packed," forming a close mosaic on one side of the rings, 

 while the serum is drawn off by capillary attraction on the other side. 



The second method Dr. Norris calls "isolation." The slide used 

 is drilled with a hole, in which a metal eyelet is inserted ; a square 

 cover-glass is strapped to the slide by one edge only, so that the 

 opposite free edge overlaps the aperture ; a small screw working in 

 the eyelet is used to carefully raise the hinge-like cover-glass. The 

 blood is introduced at one edge, and as soon as it has by capillarity 

 spread itself in a thin layer between the glasses, their two surfaces are 

 gently separated by inserting the screw and raising the cover-glass. 

 At this moment the whole bulk of the fluid passes away towards the 

 edge of the glass attached by the plaster, leaving a few corpuscles 

 adhering to each of the two glass surfaces with which the blood was 

 in contact. If this operation be performed over a strong solution of 

 osmic acid, the vapour immediately fixes the corpuscles in the condi- 

 tion in which they were at the moment of the withdrawal of the 

 serum. By this method, either with or without the action of the vapour, 

 transparent colourless corpuscles as well as normal red corpuscles are 

 found adhering to the glass. 



His third method is to change the refractive index of the serum 

 by the addition of a saturated solution of chloride of sodium. When 

 thus treated the blood is found to teem with corpuscles, previously 

 invisible, of every shade of tint. 



As to the origin of these colourless corpuscles Dr. Norris considers 

 them to be a simple transformation of the lymph-corpuscles. He states 

 that he has examined the latter in a fresh state, and that he has 

 failed to discover a nucleus ; in fact, he considers them to be simply 

 discoid non-nucleated cells, consisting of an external pellicle and 

 semifluid contents, and the appearance of nucleation he believes to 

 be always due to the action of reagents. This lymph-disk becomes 

 biconcave by a rapid process on its introduction into the blood cir- 

 culation, and can then be recognized (by the methods described) as a 

 young colourless corpuscle. Dr. Norris states that he has been able 

 to observe the conversion of the discoid lymph-cell into a biconcave 

 corpuscle. He is entirely opposed to the current view that the white 

 corpuscle of the blood is a nucleated cell ; he considers it to be a 

 mere " accidental aggregate of adhesive lymph-corpuscles," the false 

 appearance of nucleation being caused by the same post-7nortem 

 changes already described as taking place in the lymph-cell. 



Mrs. Ernest Hart,* who has undertaken a careful investigation of 

 the author's experiments, considers that his conclusions are vitiated 

 by sources of fallacy arising from the methods employed, which 

 appear to produce the appearances which he describes as normally 

 existing. In his third method it is demonstrable that the influence 

 of a saturated solution of chloride of sodium on the blood-corpuscles 

 in the fresh state is to cause about one-third of the number to 

 lose their hasmoglobin, and become transparent and colourless. 

 The longer the blood is left in contact with the salt, the greater the 

 number of corpuscles that become transparent. Mrs. Hart has found 



* Loc. cit. 



