CORPUSCLES. xxx i 



soluble coloured substance from the tegumentary frame, which is insoluble, 

 and remains behind, shrunk to about two-thirds of its original diameter. 

 To me the human blood- corpuscles, when deprived of their coloured part by 

 means of distilled water, and subsequently treated with solution of iodine, 

 appear under the microscope like somewhat thick shrunken sloughs. 



The human blood-corpuscles, as well as those of the lower animals, often 

 present deviations from the natural shape, which are most probably due to 

 causes acting after the blood has been drawn from the vessels, but in some 

 instances depend upon abnormal conditions previously existing in the blood. 

 Thus, it is not unusual for many of them to appear indented or jagged at 

 the margin, when exposed under the microscope, (fig. xv. , 3 ) and the number 

 of corpuscles so altered often appears to increase during the time of observa- 

 tion. This is, perhaps, the most common change ; but they may become 

 distorted in various other ways, and corrugated on the surface ; not unfre- 

 quently one of their concave sides is bent out, and they acquire a cup-like 

 figure. It is even a question with some observers, whether the biconcave 

 figure which the corpuscles generally present may not be due to a distension 

 of the circumferential part of an originally flat disk. Mr. Gulliver made 

 the curious discovery that the corpuscles of the Mexican deer and some 

 allied species present very singular forms, doubtless in consequence of ex- 

 posure ; the figures they assume are various, but most of them become 

 lengthened and pointed at the ends, and then often slightly bent, not unlike 

 caraway-seeds. 



The red disks, when blood is drawn from the vessels, sink in the plasma ; 

 they have a singular tendency to run together, and to cohere by their 

 broad surfaces, so as to form by their aggregation cylindrical columns, like 

 piles or rouleaus of money, and the rolls or piles themselves join together 

 into an irregular network (fig. xvn.). In a few moments after this has taken 

 place, a heaving or slowly oscillating motion is 

 observable in the mass, and the rolls may then 

 become broken up, and the corpuscles more or 

 less completely disjoined (Jones). Generally 

 the corpuscles separate on a slight impulse, and 

 they may then unite again. The phenomenon 

 is probably of a physical kind : it will take 

 place in blood that has stood for some hours 

 after it has been drawn, and also when the 

 globules are immersed in serum in place of 

 liquor sanguiuis. 



By processes, which need not here be detailed, 

 Yierordt and Welcker have estimated the number 



of red corpuscles in a cubic millimetre of human Fig- XVII. RED CORPUSCLES 

 blood. The former assigns it at upwards of COLLECTED INTO ROLLS (after 



5.000,000 ; the latter at^5,000,000 in the male, and Henle). 



4^500,000 in the female? 



Pale or colourless Corpuscles (fig xvm.). These are comparatively few in 

 number, of a rounded and slightly flattened figure, rather larger in man and 

 mammalia than the red disks, and varying much less than the latter in 

 size and aspect in different animals. In man (during health) the proportion 

 of the white corpuscles to the red is about 2 or 3 to 1000. This proportion 

 is diminished by fasting and increased after a meal, especially of albuminous 

 food. Their number compared with the red corpuscles is said to be greater 



