IS CONSTITUENTS OF THE RED BLOOD-CORPUSCLES. 



nearly all cases of amemia. " Giant blood-corpuscles " or macrocytes (10 /k and more) are con- 

 stant in pernicious amemia, and sometimes in Leukaemia, chlorosis, and liver cirrhosis {Gram). 



(3) Abnormal forms of the red corpuscles have been observed after severe burns (Lesser) ; the cor- 

 puscles are much smaller, and under the influence of the heat, particles seem to be detached from 

 them just as can be seen happening under the microscope as the effect of heat. Disintegration 

 of the corpuscles into tine droplets has been observed in various diseases, as in severe malarial 

 fevers. The dark granules of a pigment closely related to hamiatin are derived from the 

 granules arising from the disintegration of the blood-corpuscles, and these particles float in the 

 blood mel&nsemia . This condition can be produced artificially by injecting bisulphide of 

 carbon (7 to 70 of oil) subcutaneously into rabbits (Schicalbc). They are partly absorbed by the 

 colourless corpuscles, but they are also deposited in the spleen, liver, brain, and bone-marrow. 



(4) Sometimes the red corpuscles are abnormally soft, and readily yield to pressure. 

 Parasites of Blood-Corpuscles. Within the red blood-corpuscles of birds, fishes, and tortoises, 



parasites are occasionally developed in the form of round " pseudo-vacuoles " from which free 

 iiarasites are subsequently discharged (Danilewsky). In malarial conditions in man, protozoon- 

 like organisms have been seen within the red corpuscles, the Plasmodium malaria: (Mar- 

 ehiafata . 



The white corpuscles are enormously increased in number in leukaemia (J. H. Bennett, 

 Virchmc). In some cases the blood looks as if it were mixed with milk. The colourless cor- 

 puscles Beem to be formed chiefly in bone-marrow (E. Neumann), and also in the spleen and 

 lymphatic glands (myelogenic, splenic, and lymphatic leukaemia). 



11. CHEMICAL CONSTITUENTS OF THE RED BLOOD-CORPUSCLES. 



(1) The colouring matter or haemoglobin (Hb) is the cause of the red colour of 

 blood ; it also occurs in muscle, and in traces in the fluid part of blood, but in the 

 last case only as the result of the solution of some red corpuscles. Its percentage 

 composition is : C 5385, H 7 32, N 16-17, Fe 0'42, S 0*39, O 21'84 (dog). Its 

 rational formula is unknown, but Preyer gives the empirical formula C 600 , H 960 , 

 N 154 , Fe, S.j, 179 . Although it is a colloid substance it crystallises in all classes 



b of vertebrates, according to the rhombic system, 

 and chiefly in rhombic plates or prisms ; in the 

 guinea-pig in rhombic tetrahedra ; in the squirrel, 

 however, it yields hexagonal plates. The varying 

 forms, perhaps, correspond to slight differences 

 in the chemical composition in different cases. 

 Crystals separate from the blood of all classes of 

 vertebrata during the slow evaporation of lake- 

 coloured blood, but with varying facility (fig. 13). 

 The colouring matter crystallises very readily from the 

 blood of man, dog, mouse, guinea-pig, rat, cat, hedgehog, 

 ^^^ d a horse, rabbit, birds, fishes ; with difficulty from that of 



"^^^ f ^^ tne 8nee P ox > aiu l Pig- Coloured crystals are not obtained 



from the blood of the frog. More rarely a crystal is formed 

 from a single corpuscle enclosing the stroma. Crystals 

 have been found near the nucleus of the large corpuscles 

 of fishes, and in this class of vertebrates colourless crystals 

 T^\ have been observed. 



Dichroism. Haemoglobin crystals are doubly 

 Fig. 13. refractive and pleo-chromatic ; they are bluish- 



Htemoglobin crystals from blood, a, red with transmitted light, scarlet-red by reflected 

 b, human ; c, cat ; d, guinea-pig ; light. They contain from 3 to 9 per cent, water 

 e, hamster; /, squirrel. of crystallisation, and are soluble in water, but 



more so in dilute alkalies. They are insoluble in alcohol, ether, chloroform, and 

 fats. The solutions are dichroic : red in reflected light, and green in transmitted 

 light. 



In the act of crystallisation the haemoglobin seems to undergo some internal change. Before 

 it crystallises it does not diffuse like a true colloid, and it also rapidly decomposes hydric 

 peroxide. If it be redissolved after crystallisation, it diffuses, although only to a small extent, 

 but it no longer decomposes hydric peroxide, and is decolorised by it. [The presence of 

 favours crystallisation. ] r 





