CHANGES IN THE FORM OF THE RED BLOOD-CORPUSCLES. 9 



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 decom- 

 posing blood, as well as after the action of many other reagents. 



Fig. 4. 



Red blood-corpuscles, showing various changes of shape a, b, normal human red 

 corpuscles, with the central depression more or less in focus; c, d, e, mulberry 

 forms; g, h, crenated corpuscles; Tc, pale decolourised corpuscles; I, stroma; 

 /, a frog's blood-corpuscle, partly shrivelled, owing to the action of a strong 

 saline solution. 



Action of Heat. When blood is heated, on a warm stage, to 52C. 

 the corpuscles begin to undergo 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 surround- 

 ing fluid, a proof that heat destroys the histological individuality of 

 the corpuscles (Max Schultze). If the heat be continued, the corpuscles 

 are ultimately dissolved. 



Cytozoon or Wurmchen Gaule's Experiment. The following remarkable 



observation made by Gaule deserves mention here : A few drops of freshly- 

 shed frog's blood are mixed with 5 cc. of 0'6 per cent, solution of common salt, 

 and the mixture deh'brinated by shaking it along with a few cc. of mercury. A 

 drop of the defibrinated blood is examined on a hot stage (30-32C.) under a 

 microscope, when a protoplasmic mass, the so-called "wiirmcJien," 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 

 R,ay Lankester, who called the parasite Drepanidium ranartim. 



If a finger moistened with blood be rapidly drawn across a warm 

 slip of glass, so that the fluid dries rapidly, very remarkable corpuscle- 

 shapes, showing their great ductility and softness, are observed under 

 the microscope. 



