FORM AND COLOUR OF THE BLOOD-CELLS. 175 



and very much diminished in thickness, so that they resembled 

 lamellae rather than discs; moreover, they were very much dis- 

 torted, and some of them had a jagged appearance. 



1 volume of blood, mixed with half a volume of a solution of 

 sulphate of magnesia, became of a light vermilion colour, and 

 remained so even after 18 hours; the fluid had then become very 

 ropy ; there was very little sinking of the corpuscles, which had 

 assumed a biscuit-like form and had their long diameter increased ; 

 their discoid form was somewhat distorted, and they were often a 

 little jagged at the edges. 



On treating 1 volume of blood with two-thirds of a volume of a 

 solution of hydrochlorate of ammonia, it first assumed a vermilion 

 colour, but, after 24 hours, appeared far darker than blood treated 

 with sulphate of soda, although scarcely darker than unmixed 

 blood ; after 1 hour and 5 minutes the corpuscles began to sink, 

 but after 10 hours, there was no true separation of serum ; on the 

 surface the mixture was red, and only slightly transparent ; it was, 

 moreover, very ropy. The corpuscles were spherical, and smaller 

 in diameter than the original discs. 



1 volume of blood, when mixed with half a volume of solution of 

 cane-sugar (1 part of sugar to 22 parts of water), became of a some- 

 what lighter red colour ; the blood-corpuscles were moderately con- 

 tracted, and began to sink in an hour and a quarter, the sinking 

 extending to l-16th of the volume in 18 hours; the serum was 

 perfectly clear and colourless ; the clot was of a somewhat lighter 

 colour than that of ordinary blood, and the corpuscles were still 

 moderately contracted. 



1 volume of blood, on the addition of 0*7 of a volume of a 

 solution of gum arable (1 part in 20 of water), became very dark, 

 and the blood-corpuscles were distended and almost spherical; 

 they began to sink in three-quarters of an hour, and after 18 hours, 

 had sunk to the extent of l-40th of the volume; the blood had a 

 blackish red colour, and was very tenacious. 



100 volumes of blood mixed with an aqueous solution* of 

 arsenious acid, assumed a somewhat light red colour ; the blood- 

 corpuscles were unchanged, and, after 24 hours, had sunk to the 

 extent of l-10th of the volume of the fluid ; the serum was then 

 red, and the blood-corpuscles were spherical and had no central 

 shadow ; several, that were lying on their edge, were reniform ; all 

 were increased in thickness. 



* [The number of volumes of the solution of arsenious acid, and its strength, 

 are omitted by the author, apparently by an oversight. G. E. D.] 



