PHILOSOPHICAL SOCIETY OP WASHINGTON. 



21 



In each of these measurements of humau blood, the great ma- 

 jority of the corpuscles ranged from twelve to seventeen divisions 

 of the eye-piece micrometer; that is, from .00024 to .00034 of 

 an inch. Out of the whole number measured, six were as small 

 as ten divisions, and one as large as eighteen divisions ; laro-e 

 and small forms were not searched for, however. The size most 

 frequently measured was fifteen divisions, or .00030 of an inch. 



Examination of Red Blood- Corpuscles of the Dog from five 

 Individuals. 



In each of these measurements of dogs' blood, precisely as in 

 the case of those of human blood, the great majority of the cor- 

 puscles measured from twelve to seventeen divisions of the eye- 

 piece micrometer (.00024 to .00034 of an inch). Out of the 

 whole number measured, four were as small as ten divisions, but 

 none lai'ger than seventeen were encountered. As with the 

 human blood, however, large and small forms were not searched 

 for, but all the perfectly formed corpuscles brought into view by 

 the movement of the stage, were measured as they passed under 

 the micrometer without selection until the required number was 

 recorded. The size most frquently measured was fifteen divi- 

 sions, or .00030 of an inch, precisely as in the case of human 

 blood. 



It will be observed that three of the above means for human 

 blood, Nos. 1, 3, and 7, are a trifle larger than any of those of 

 dogs' blood, and two of the latter, Nos. 7 and 8, are a trifle 

 smaller than any of those for human blood. All the other 

 means for the dog are withm the range of the values found for 

 human blood, and the majority of them are each identical, even 

 to the last decimal place, with some one of those found for man. 



The author has not made systematic measurements of the blood 

 of other animals besides the dog, whose blood could not be dis- 



