STRUCTURE OF COLORED BLOOD-CORPUSCLES. 75 



mum measurement recorded in his table is .0045 mm., and the maximum, 

 though not in the same specimen, .0097 mm. He remarks : " I have always, 

 both in animals and in man, found the transverse diameter of the blood- 

 corpuscles of one and the same individual vary from one-fourth to one-half of 

 the mean measurement ; and it appears that all the sizes lying between the two 

 extremes are present in tolerably equal numbers, with the exception of the 

 smallest corpuscles, which occur for the most part singly and at intervals." * 



Max Schultze distinguished in his own and other persons' healthy blood two 

 forms of colored corpuscles, viz. : globular and disk-like ; the globular, few in 

 number, vary from .005 to .006 mm. in size ; and from these there are grad- 

 ual transitions to the ordinary disks, which measure from .008 to .010 mm. t 



The smallest colored corpuscles which Klebs reported t having found in his 

 own blood varied from .0058 to .0066 mm. ; but in blood from the corpse of 

 a leucaemic child he observed a few as small as .00416 mm. 



Woodward said : " The truth is that not only do the individual corpuscles 

 in every drop of blood vary considerably in size, but as might be anticipated 

 from this very fact, the average size obtained by measuring a limited number 

 of corpuscles (50 to 175, still more in the case of but 10 to 50, as usually 

 practiced), varies considerably, not only between different individuals, but 

 also between different parts of the very same drop of blood." Both the maxi- 

 mum and the minimum which he found viz.: the 396 millionths and the 

 216 millionths of an inch, or .01005 and .00548 mm. were present in the 

 same field of one drop. 



Berchon and Perrier|| state that the colored blood-corpuscles of the 

 fo3tus and the newly born are on an average smaller than those of 

 adults. The extremes given are: minimum, .0031 to .0062 mm., and 

 maximum, .0091 to .0093 mm. ; but they do not mention that the extremes 

 occurred in one and the same case. More recently, PerrierU measured 

 blood-corpuscles of thirty-five individuals of different ages, and found that 

 those of .010 mm. were very frequent in the first days after birth, while later 

 they occurred much more rarely. After the first year, blood-corpuscles meas- 

 uring .0093 mm. were rarely present in greater proportion than ten in a hun- 

 dred ; and in adults often absent. Such of .0043 mm. occurred most often in 

 the aged and in children. The diameter of the great mass at every age varies 

 from .0050 to .0087mm. ; within these limits those of .0075 mm. are most 

 frequent and never absent. The form of the smaller is more or less globular ; 

 the larger are flattened. 



* Cited by Woodward, " On the Similarity between the Bed Blood-corpuscles of Man and 

 those of certain other Animals, especially the Dog : considered in connection with the diagno- 

 sis of Blood-stains in criminal cases." American Journal of Medical Sciences, Jan., 1875. 

 Monthly Microscopical Journal, Feb. 1, 1875, p. 69. 



t " Ein heitzbarer Objecttisch uud seine Verwendung bei Untersuchungen des Blutes." 

 Archiv fur Mikroskopische Anatomie, vol. i. (1865), p. 35. 



t " TJeber die Kerne und Scheinkerne der rotlien Blutkorperchen der Saugethiere." 

 Virchow's Archiv fiir pathologische Anatomie und Physiologie und f iir Kliuische Medicin : 

 vol. xxxviii. (1867), p. 195. 



" The Application of Photography to Micrometry, with special reference to the micro- 

 metry of blood in criminal cases." Transactions of the American Medical Association, vol. 

 xxvii. (1876), p. 303-315. 



|| " Note sur les globules du sang chez le fo3tus." Bordeaux Medical., p. 123 and 237 ; 

 Canstadt's Jahresbericht for 1875, I., p. 46. 



f " Sur les variations du diametre des globules rouges du sang dansl'espece humaine, au 

 point de vue de 1'espertise legale." Compt. liendus, torn. 84 (1877), No. 24, p. 1404. 



