

CHANGES OF FORM OF THE CORPUSCLES. 7 



discs. These discs rapidly cohere, owing to capillarity, and form rouleaux. If the discs be 

 completely submerged they remain apart, as occurs with unaltered blood-corpuscles within the 

 blood-vessels. If, however, the corpuscles be dipped in petroleum, and then placed in water, 

 rouleaux are formed.] If reagents which cause the corpuscles to swell up be added to the blood, 

 the corpuscles become globular and the rouleaux break up. According to E. Weber and Suchard, 

 the uniting medium is not fibrin (although it may sometimes assume a fibrous form), but belongs 

 to the peripheral layer of the corpuscles. 



(c) Changes of Form. The discharge of a Leyden jar causes the corpuscles to 

 crenate, so that their surfaces are beset with coarse or fine projections (fig. 6, c, d, 

 e, g, h) ; it also causes the corpuscles to assume a spherical form (i, i), and they 

 a ,, 



i. . k 



Red blood-corpuscles, a, b, normal human red corpuscles, the central depression more or less 

 in focus ; c, cl, c, mulberry, and g, h, crenated forms ; k, pale corpuscles decolorised by 

 water ; I, stroma ; /, frog's blood-corpuscle acted on by a strong saline solution. 



become smaller than normal. The corpuscles so altered are sticky, and run together 

 like drops of oil, forming larger spheres. The prolonged action of the electrical 

 spark causes the haemoglobin to separate from the stroma (), whereby the fluid 

 part of the blood is reddened, while the stroma is recognisable only as a faint 

 shadow (/). Similar forms are to be found in decomposing blood, as well as after 

 the action of many other reagents. Heat. When blood is heated, on a warm 

 stage, to 52 C. the corpuscles exhibit remarkable changes. Some of them become 

 spherical, others biscuit-shaped ; some are perforated, while in others small portions 

 become detached and swim about in the surrounding fluid, a proof that heat 

 destroys the histological individuality of the corpuscles. If the heat be continued, 

 the corpuscles are ultimately dissolved ( 10, 3). 



Heat acts like the addition of a concentrated solution of urea to blood. If strong pressure 

 be exerted upon a microscopic preparation, the blood-corpuscles may break in pieces. The 

 latter process is called haemocytotrypsis, in contradistinction to that of solution of the cor- 

 puscles or hsemocytolysis. 



If a finger moistened with blood be rapidly drawn across a warm slip of glass, so that the 

 fluid dries rapidly, the corpuscles exhibit very remarkable shapes, showing their great ductility 

 and softness. 



Cytozoon Gaule's Experiment. A few drops of freshly-shed frog's blood are mixed with 5 

 c.c. of 0'6 per cent, solution of common salt, and the mixture defibrinated by shaking it along 

 with a few c.c. of mercury. A drop of the defibrinated blood is examined on a hot stage 

 (30-32 C.) under a microscope, when a protoplasmic mass, the. so-called " Wiirmchen," 

 escapes with a lively movement from many corpuscles, and ultimately dissolves. Similar 

 "cytozoa" were discovered by Gaule in the epithelium of the cornea, of the stomach and 

 intestine, in connective-tissue, in most of the large glands, and in the retina (frog, triton). In 

 mammals also he found similar but smaller structures. Most probably these structures are 

 parasitic in their nature, as suggested by Ray Lankester, who called the parasite Drepanidium 

 ranarum. 



[Staining Reagents. Such reagents as magenta, picro-carmine, carmine, and 

 many of the aniline dyes, stain the nucleus deeply when such is present, and 

 although they must traverse the haemoglobin to reach the nucleus, the haemoglobin 

 itself is not stained. When no nucleus is present, therefore, the corpuscles are not 



