THE BLOOD-PLATES. 



49 



being finally dissolved. Where they are collected together they readily 

 cohere into masses (7), and pass over into aggregations resembling 

 stroma-fibrin, which in coagulated blood may be united with shreds 

 of fibrin (6, 8). 



Bizzozero believes that they furnish the material for the fibrin in the process 

 of coagulation, and he, as well as Eberth and Schimmelbusch, attribute the initial 

 formation of white thrombi to them. According to Lowit they are formed from 

 disintegrated leukocytes, and according to Lilienfeld from the nuclein and albumin 

 of the nuclei of these cells. According to Wooldridge they are globulin-precipi- 

 tates from the plasma. J. Arnold followed their extrusion and detachment from 

 ery throcy tes ; in smaller measure they are derived from leukocytes. Halla found 

 them increased in pregnant women, Mosen after hemorrhage, Afanassiew in the 

 presence of regenerative states of the blood, Cadet in association with hunger, 

 Hayem after the crisis of certain infectious diseases, and Fusari in cases of afebrile 

 anemia. They are diminished in the presence of fever, as well as of severe infec- 

 tions and blood-stasis, and also after injection of leech-extract. The blood of 

 cold-blooded animals and of birds contains also small spindle-shaped, nu- 

 cleated cells. 



FIG. 9. "Blood-plates" and Their Derivatives: i, a red blood-corpuscle on the flat; 2, on the side; 3, unchanged 

 blood-plates; 4, lymph corpuscle, surrounded by blood-plates; 5, altered blood-plates; 6, lymph corpuscle 

 with two heads of fused blood-plates and threads of fibrin; 7, group of fused blood-plates; 8, small group ot 

 partially dissolved blood-plates with fibrils of fibrin. 



Demonstration in Mass. If 10 parts of blood are mixed with i part of a 0.2 

 per cent, solution of ammonium oxalate in 0.7 per cent, solution of sodium chlorid, 

 and the mixture is centrifugated, a grayish-red layer principally of leukocytes 

 will form above the ery throcy tes, and over this a white layer consisting almost 

 solely of blood-plates, while above all is the clear plasma. 



In addition, a few small granules, so-called elementary granules, 

 occur in the blood. These are irregular masses of protoplasm derived 

 from disintegrated leukocytes or blood-plates. 



According to H. F. Miiller there are constantly present also, especially after 

 the ingestion of food, minute, globular, highly refracting granules, which are not 

 fat, and which he designates blood-dust, or nemokonien. 



Coagulated blood contains delicate threads of fibrin (Fig. 9, 6, 8), 

 strung like a spider's web between the corpuscles. They become iso- 

 lated after dissolution of the corpuscles. Where many such threads 

 occur together a nodular accumulation takes place. 



