THE BLOOD AND THE LYMPH. 325 



when the crass amentum presents a superficial colourless, or 

 whitish stratum (inflammatory crust), consisting only of the 

 coagulated fibrin and colourless blood-cells, together with the 

 fluid with which they are imbued. 



The coloured or red blood-globules ; or simply blood-globules, 

 in which alone the colouring matter of the blood resides, are 

 minute non-nucleated cells of a flattened, 

 lenticular form, which are contained in -. ' ' 



0(fi) at 



the blood in such vast quantity, that, «(S) (§> 

 unless it be diluted with serum, they do _*'~ 

 not readily admit of exact investigation, 1 

 appearing of themselves to constitute 

 the blood. However important it would 

 be to know accurately the proportion of the blood-globules to 

 the plasma, their number and their volume, all researches 

 hitherto have failed, owing to the difficulty of the subject; and 

 even the very recent statements of Schmidt, according to 

 which 47 — 54 parts of moist blood-globules exist in 100 parts 

 of human blood, can only be described as approximative. One 

 method only can be successful, consisting in the direct enume- 

 ration of the globules in accurately determined quantities of 

 blood, and as precise a determination as possible of the 

 volume of the individual corpuscles (Vierordt) ; but this 

 method, if applied in such a way as to ensure correct results, 

 demands so much time and trouble, that it cannot be expected 

 to obtain general application, and we must be contented with 

 an accurate investigation of the total quantity of blood-globules 

 in a single or in some few instances, an undertaking in which 

 Vierordt is now engaged. 



The red blood-globules, more minutely examined, present 

 the following characters : Their form is usually that of a 

 biconcave or plane, orbicular disc, with rounded borders, and 

 consequently they present a different aspect to the observer, 

 according as the surfaces or borders are turned towards him. 



Fig. 291. Blood-globules of Man : a, viewed on the flat surface ; b, on the edge ; 

 c, united into rouleaux ; d, rendered spherical by the addition of water ; e, rendered 

 colourless by the same agent ;/, blood-globules shrunken by the drying up of the fluid. 



1 [We must caution the reader against being guided by this statement. Nothing 

 is easier tban the examination of the blood as it is, — nothing more likely to mislead 

 than the practice of diluting it with any fluid whatsoever. — Eds.] 



