INFLUENCES AFFECTING PHYSICAL RED BLOOD-CORPUSCLES. 35 



not capable of diffusing into the red blood-corpuscles, as, for instance, 

 solutions of potassium, of iron, and of manganese, although other sub- 

 stances do enter, as, for instance, sugar and chloroform. 



Nucleated erythrocytes are undoubtedly cells, while the non-nucleated ery- 

 throcytes cannot properly be so considered. The latter have, therefore, been 

 designated blood-plastids. 



INFLUENCES AFFECTING THE PHYSICAL PHENOMENA OF RED BLOOD- 

 CORPUSCLES. 



The color of the red corpuscles is changed characteristically by a 

 number of gases. Thus, oxygen, therefore also the air, renders the 

 blood scarlet red, deficiency of oxygen renders it dark bluish red, carbon 

 monoxid renders it cherry red, nitrogen monoxid renders it violet red. 

 All agents that cause marked contraction of the erythrocytes induce a 

 bright scarlet-red color; as, for instance, concentrated solution of sodium 

 sulphate, from the action of which the corpuscles become mulberry- 

 shaped or distorted into the shape of a key, and in a measure attenu- 

 ated. The color thus produced is brighter than is ever observed in the 

 arteries. Those agents that make the corpuscles globular, as particu- 

 larly water, cause the color of the blood to become darker. 



If a dry preparation of blood be treated with concentrated solution of methyl- 

 ene-blue diluted half with water some of the erythrocytes, particularly degenerated 

 ones, become stained. It is the larger ones that are especially numerous in the 

 presence of anemia and leukemia. 



Change in Position and Form. A phenomenon frequently observed 

 in recently shed blood is the arrangement of the corpuscles like rolls of 

 coin (Fig. i, A, 3). 



The conditions that increase the coagulability of the blood favor this phenome- 

 non, which is to be attributed, in addition to the attraction of the discs, to the 

 formation of a viscid substance. The condition is favored by warming moderately 

 the slide upon which the fresh drop of blood is received. If under such circum- 

 stances agents are added to the blood capable of causing the corpuscles to swell, 

 the rolls separate as the individual corpuscles are transformed into globules. The 

 adhesive substance uniting the erythrocytes, and which not rarely is drawn out 

 into filamentous threads, is derived from the peripheral layer of the corpuscles. 

 It consists of the stroma-fibrih, formed on the surface of the corpuscles in conse- 

 quence of the inception of an injury at the periphery, and which has become viscid. 



The changes in shape that the erythrocytes may gradually undergo 

 after leaving the body, up to the point of dissolution, are of especial 

 interest. Some agents bring this series of changes about in rapid suc- 

 cession. If, for instance, blood is exposed to the action of the spark of 

 a Leyden jar, all of the corpuscles become at first mulberry-shaped, 

 that is, the surface becomes rough and soon covered with at times 

 small, at other times large, round nodules (Fig. 4, c d e). If the action 

 be more pronounced the blood-corpuscles become almost globular, with 

 many projecting points, thorn-apple-like (gh); this is probably an 

 indication of the death of the corpuscle. At a further stage the action 

 causes the corpuscles to assume a perfectly globular shape (ii). In 

 this form they appear smaller than normal, as their disc-shaped mass is 

 contracted into a sphere with a lesser diameter. The globules thus 

 formed are viscid, and adjacent corpuscles readily adhere to one another 

 'and like fat-globules they may unite to form larger spheres. If the 



