22 CHANGES OF THE RED AND WHITE BLOOD-CORPUSCLES. 



of the blood, the " llood-platcs " of Bizzozero ; pale, colourless, biconcave 

 discs of variable size (mean, 3 /uC). According to Hayem (who called 

 these structures H^EMATOBLASTS, supposing that they were an early 

 stage in the development of the red blood-corpuscles), they are forty 

 times as numerous as the leucocytes. These blood-plates may be 

 recognised in circulating blood, as in the mesentery of the guinea-pig. 

 They are precipitated in enormous numbers upon threads suspended in 

 fresh-shed blood (Bizzozero). They may be obtained from blood 

 flowing directly from a blood-vessel, on mixing it with 1 per cent, 

 solution of osmic acid or Hayem's fluid (mercury bichloride 0'5, sodium 

 carbonate 5, sodium chlorate 1, distilled water 200 Laker). They 

 undergo a rapid change in shed blood (Fig. 7, 5), disintegrating, 

 forming small particles, and ultimately dissolving. When several occur 

 together they rapidly unite, form small groups (7), and collect into 

 masses resembling " stroma-fibrin " (p. 48). These masses may be 

 associated in coagulated blood with fibrils of fibrin. 



Bizzozero believes that they yield the material for the formation of fibrin during 

 coagulation of the blood. It is not yet determined whether they are derived from 

 partially disintegrated leucocytes, or whether they are independent formations. 

 Along with the leucocytes they are concerned in the formation of fibrin (Hlava). 

 These structures were known to earlier observers (Max Sehultze, Puess, and 

 others) ; but their significance has been variously interpreted. 



IV. Blood, especially after a microscopic preparation has been made 

 for a short time, is seen to contain ELEMENTARY GRANULES (Fig. 6, F), 

 [/.('., the elementary particles of Zimmermann and Beale. They are 

 irregular bodies, much smaller than the ordinary corpuscles, and appear 

 to consist of masses of protoplasm detached from the surface of 

 leucocytes, or derived from the disintegration of these corpuscles, or 

 of the blood-plates. Others, again, are completely spherical granules, 

 either consisting of some proteid substance or fatty in their nature. 

 The protoplasmic and the proteid granules disappear on the addition 

 of acetic acid, while the fatty granules (which are most numerous after a 

 diet rich in fats) dissolve in ether]. 



V. In COAGULATED blood, delicate fibrils or threads of FIBRIN (Fig. 

 G, E and G, S, G) are seen, more especially after the corpuscles have 

 run into rouleaux. At the nodes of these fibres are found granules 

 which closely resemble those described under III. 



[These granules and fibres are stained by magenta and iodine, but 

 not by carmine or picro-carmine (Ranvier).] 



10. Abnormal Changes of the Red and White 

 Blood-Corpuscles. 



(1.) All haemorrhages diminish the number of red corpuscles (at most one- 

 half), and so does menstruation. The loss is partly covered by the absorption of 



