FOKM AND SIZE OF THE BLOOD-COKPUSCLES. 



zooid, to separate from the cecoid (fig. 7, d). The zooid may shrink from the periphery of the 

 corpuscle, or it may pass out of the corpuscle altogether (Briicke) ; Briicke regards the stroma in 

 a certain sense as a house, in which the remainder of the substance of the corpuscle, the chief 

 part endowed with vital phenomena, lives. 11. Strong solutions of acids dissolve the cor- 

 puscles ; more dilute solutions cause precipitates in the haemoglobin. This is easily seen with 

 carbolic acid (Hills and Landois, Stirling and Rannie). 12. Alkalies of moderate strength 

 cause sudden solution. A 10 per cent, solution of potash, placed at the edge of a cover- 

 glass, shows the process of solution going on under the microscope. At first the corpuscles 

 become globular, and so appear smaller, but afterwards they burst like soap-bubbles. [13. 

 NH 4 C1 injected into the blood causes vacuolation of the red corpuscles (Bobritzky). 14. Sodic 

 salicylate, benzoate, and colchicin, dissolve the red corpuscles (N. Paton).] 

 [Tannic Acid. A freshly prepared solution of tannic acid has a remarkable effect on the col- 

 oured blood-corpuscles of man and animals causing a separation of the haemoglobin from the 

 stroma ( W. Roberts). The usual effect is to produce one or more granular buds of haemo- 

 globin on the side of the corpuscles (fig. 7, b, c) ; more rarely the haemoglobin collects around 

 the nucleus, if such be present (fig. 7, d), or is extruded, as shown in fig. 7, e.] 

 [Ammonium or Potassium Sulpho-cyanide removes the haemoglobin, and reveals a reticular 

 structure intra-nitclear plexus of fibrils (Stirling and Rannie). ] 



The Amount of Gases in the blood exercises an important influence on their solubility. The 

 corpuscles of venous blood, which contains much C0. 2 , are more easily dissolved than those of 

 arterial blood ; while between both stands blood containing CO. When the gases are com- 

 pletely removed from the blood, it becomes lake-coloured. 



Salts increase the resistance of the corpuscles to physical means of solution, while 

 they facilitate the action of chemical solvents. 



If certain salts be added in substance to blood, they make blood lake-coloured ; potassic 

 sulphocyanide, sodic chloride, &c. (Kowaleiosky). 



Resistance to Solvents. The red blood-corpuscles offer a certain degree of 

 resistance to the action of solvents, 



Method. Mix a small drop of blood with an equal volume of a 3 per cent, solution of sodic 

 chloride, and then add distilled water until all the coloured corpuscles are dissolved. Fill the 

 mixer (fig. 3) up to the mark 1 with blood obtained by pricking the finger, and blow this blood 

 into an equal volume of a 3 per cent, solution of NaCl previousl} 7 placed in a hollow in a glass 

 slide. Mix the fluids, and the corpuscles will remain undissolved. By means of the pipette 

 add distilled water, and go on doing so until all the corpuscles are dissolved ; which is ascertained 

 with the microscope. In normal blood, solution of the corpuscles occurs after 30 volumes of 

 distilled water have been added to the blood (Landois). 



There are some individuals whose blood is more soluble than that of others ; their corpuscles 

 are soft, and readily undergo changes. Many conditions, such as cholpemia, poisoning with 

 substances which dissolve the corpuscles, and a markedly venous condition of the blood, affect 

 the corpuscles. Interesting observations may be made on the blood in infectious diseases, 

 hemoglobinuria, and in cases of burning. In anaemia and fever, the capacity for resistance 

 seems to be diminished. 



6. FORM AND SIZE OF THE BLOOD-CORPUSCLES OF ANIMALS. All 

 mammals (with the exception of the camel, llama, alpaca, and their allies), and the 

 cyclostomata amongst fishes, e.g., Petromyzon, possess circular bi-concave non- 

 nucleated disc-shaped corpuscles. Elliptical corpuscles without a nucleus are found 

 in the above-named mammals, while all birds, reptiles, amphibians (fig. 1, B, 1, 2), 

 and fishes (except cyclostomata) have nucleated elliptical bi-convex corpuscles. 



