276 The Structure of Colored Blood-Corpuscles. 



are not all of the same size in the same animal, some being a 

 little larger than others," 1 etc. Hewson's editor, Oulliver, 

 who has made a very large number of measurements of red 

 blood-corpuscles of different animals, and is " our highest 

 authority upon the subject," said of his own elaborate 

 tables : " We are only speaking now of the average size, 

 for they vary like other organisms ; so that in a single drop 

 of the same blood you may find corpuscles either a third 

 larger or a third smaller than the mean size, and even still 

 greater extremes;" 2 and more recently, 3 "But as I 

 have long since shown, the corpuscles in one species of the 

 vertebrate class as seen in a single individual thereof, vary so 

 much in size that their average dimensions cannot be deter- 

 mined with absolute precision ; and were this fact kept in 

 view much needless discussion might be spared." 



Beale, also, long ago called attention to the fact that 

 " corpuscles may be found which are not more than the fifth or 

 sixth of the size of an ordinary blood-corpuscle." 4 Again : 

 " the red corpuscles vary in size, and more than is usually 

 supposed,"^ and again : " It is generally stated that 

 the red blood-corpuscles of an animal exhibit a certain 

 definite size ; but it will be found that they vary extremely, 

 so that corpuscles exist of various dimensions." 6 



WelcJcerl found in the blood of Dr. Schweigger-Seidel 

 colored blood- corpuscles as small as .0051, and as large as 



(1) Philosophical Transactions, vol. 63, Part 2, p. 320 (Read June 24, 1773). The works of 

 William Hewson, F. E. S., Edited with an Introduction and Notes, by Geo. Gulliver, F. R. 

 8. London. Published by the Sydenham Society, 1846 : p. 234. 



(2) " Lectures on the Blood of Vertebrata." Medical Times and Gazette, vol. H of 1862, 

 p. 157. 



(3) " Comparative photographs of blood-disks." Monthly Microscopical Journal, No- 

 vember, 1876, p. 240. 



(4) Archives of Medicine, voin. (No.VIII.)p. 236, and Quarterly Journal of Microscopical 

 Science, April-May, 1861 ; p. 249. 



(6) " Observations upon the Nature of the Red Blood-Corpuscle." Transactions of the 

 Microscopical Society of London (Read Dec. 9, 1863), vol. XII., N. 8., p. 37. Quarterly 

 Journal of Microscopical Science, Jan., 1864. 



(6) The Microscope in its Application to the Practice of Medicine, 3d Edition. Repub- 

 lished in Philadelphia, 1867 ; p. 170. 



(7) " Grosae, Volum und Oberflache uud Farbe der Blutkbrperchen bei Menschen and 

 bei Thleren." Z»it»chrlft fiir rationeUe Medicin, S. Ill, vol. XX. (1868), p. 237. 



