MICROSCOPICAL DIAGNOSIS. 29 



Schmidt says that over 90 per cent, of the red corpuscles found in 

 a single specimen are of the same dimensions. This much, how- 

 ever, can be said; that, after measuring a large number of corpus- 

 cles if their average diameter be found either the 1-3500 or 1-3200 

 of an inch, or any fractional part between these two, the blood may 

 be that of man. It need not necessarily be that of man, for all 

 authorities agree that the blood of the monkeys, baboons, etc., 

 beaver, porcupine, guinea-pig, and a few other animals have cor- 

 puscles identical with those of man. Yet only the blood from cer- 

 tain of the more common inferior animals would be liable to enter 

 a medico-legal contest. We refer especially to the dog, cat, hog, 

 horse, sheep and ox. 



Before considering these cases, this significant fact should be 

 borne in mind; the blood of these animals has not been studied 

 with anything like the care and time bestowed upon human blood. 

 It follows, then, that if the blood of these animals should be 

 studied as carefully, we would find as great a variation in the size 

 of their red corpuscles as exists in man; further, there would be as 

 great a variation from the size given by Gulliver as is true in the 

 case of man. As each investigator gives a particular size to the 

 human red corpuscles, all varying from that given by Gulliver; so, 

 we have every reason to believe, would each investigator give his 

 particular size to the red corpuscles of the lower animals, all vary- 

 ing from Gulliver. 



Can the blood of the dog be told from that of man? From the 

 table of Gulliver we learn that there is a difference, such a differ- 

 ence as exists between the 1-3200 and the 1-3500 of an inch. 

 Woodward, however, has completely settled this question. He says, 

 "The average of all the measurements of human blood I have 

 made, is rather larger than the average of all the measurments of 

 dog's blood. But, it is also true that it is not rare to find specimens 

 of dog's blood in which the corpuscles range so large that their 

 average size is larger than that of many samples of human blood." 

 The mean average of corpuscles in 22 drops of human blood (1766 

 corpuscles) ranged from .000,309 to .000,343 of an English inch. 

 Nearly the same number of corpuscles of dog's blood gave .000,- 

 396 to .000,340 of an inch. Monthly Microscopical Journal, 1876, 

 P- 132. 



