BLOOD. 103 



These distinctions are sufficient to prevent tliem from 

 being mistaken for blood-globules. Globules of oil may be 

 immediately recognized by their vrell-defined dark edge, and 

 by their great refractive power. They do not rotate^ and are 

 not granular, but perfectly transparent. 



The size of the blood-corpuscles varies in different animals. 



In man, the diameter varies, according to Wagner,^ from 

 "0004 to •000.2 of a French inch ; according to ^Miiller,- fi'om 

 •00035 to -000.23, and according to Schultz', from -00036 

 to '00031. The thickness, according to the last observer, 

 may be estimated at -OOOOSo of the same measure. Of all 

 the mammalia, the iiiminants seem to possess the smallest 

 blood-globides. Wagner has given the following proportions : 

 In man and monkevs ^,th of a line = 3. 

 Carnivora . . ^J^^th of a line = 4. 



Ruminantia . ^^th of a line = 5. 



In addition to these admeasurements, the following a/e de- 

 sening of notice : Nasse fixed then* average diameter at '00033, 

 the maxima and minima being -00036 and -0003 ; Bowerbank 

 places their average diameter at from -00035 to -000.27, the 

 exti'eme limits being -00054 and -00021 respectively ; Owen 

 at -00028 ; and Gulliver at -0003 of an inch. 



The dimensions of the blood-corpuscles in the following 

 animals have been measiu'ed : 



Ape (Simla callitrix) -00037"* (Prevost and Dumas). 



Cat -00028 ; dog -00031 (Schultz) ; rat and mouse about 

 •00025 (Wagner). 



Sheep -0002 (Schultz and Wagner) ; ox -0002 (Schultz) and 

 •00024 (Wagner); goat -00017; chamois -0002 (Prevost and 

 Dumas); horse -00031 — -00027 (Schultz). According to Wag- 

 ner, the diameter in rats, mice, hares, and squirrels, varies 

 from -00025 to -00020. 



The blood-corpuscles of bii'ds, fishes, and amphibia are el- 

 liptical. The following ai'e the results of some of the best 

 authenticated measurements : 



Common fowl : length -00062 ; breadth -00036 ; thickness 

 -00013 (Schultz). According to Dumas and Prevost, the long 



' Nachtrage zur Physiologic des Blutes, 1838, p. J. 

 * Physiologic des Menschcn, vol. 1. p. 106. 

 ■* System der Cirkulation. p. 14. 

 ^ French inches. 



