THE BLOOD. 51 



The observer, having satisfied himself of the accuracy of 

 the various facts brought under his notice, in the next place 

 will be prepared to enter into the important questions as to 

 the origin and destination of the globules of the blood. We 

 will consider first the origin of the white globules. 



OKIGIN OF THE GLOBULES OF THE BLOOD. 



The origin and end of the blood globules ! Whence do 

 they come, and whither do they go ? These are questions 

 of the highest importance ; and it could be wished that the 

 replies to them were of a more satisfactory and definite nature 

 than those which we are about to make will, it is feared, be 

 considered. 



Origin of the White Globules. Various opinions have been 

 entertained in reference to the nature and origin of the white 

 corpuscles of the blood, the principal of which we will now 

 proceed to notice. 



One of the earliest notions formed respecting the white 

 corpuscles was that of Hew son, who believed that they were 

 to be considered as the nuclei of the red blood corpuscles, and 

 hence he denominated then% " central particles : " to this con- 

 clusion Hewson was doubtless led by observing the great and 

 remarkable resemblance which exists between the nuclei of 

 the blood globules of certain animals and the white corpuscles 

 themselves. 



Two facts, however, are known, which satisfactorily prove 

 that the denomination of central particles is not applicable to 

 the white corpuscles, and that they do not form the nuclei of 

 the red blood discs : the first of these is, that no nuclei exist 

 in the true blood globules of the entire class of mammalia in 

 which white corpuscles are abundantly encountered, and the 

 second is the great difference in size observed between the 

 nuclei and the white corpuscles in those animals in which the 

 two organisms exist together in the blood. 



An opinion somewhat similar to the above has been held 

 by some observers, viz. that the white corpuscles are to be 

 regarded as the " escaped nuclei " of the red blood corpuscles. 

 The facts adduced to disprove the former notion respecting 



