G8 Transactions of the 



hody. A fitting analogy to the process of development of the blood 

 corpuscles is found in that of the spermatozoa, the origin and 

 development of which occurs within the cells of the seminal tubules. 

 Not only in this, but also in the difference which exists in the form 

 and size of these bodies in different classes and orders of animals, a 

 striking analogy is to be found. 



In conclusion, I shall still mention a phenomenon which I acci- 

 dentally observed, and which, peculiar as it is, will only corroborate 

 to a certain extent my views regarding the metamorphosis of the 

 colourless into the coloured blood corpuscles. In examining the 

 urine of a man sufi'ering from chronic inflammation of the kidneys, 

 I met in the sediment— consisting mainly of pus mixed with a 

 little blood — with a clear double-contoured cell, attached to a pus 

 corpuscle (colourless blood corpuscle ?) (Fig. 10). Within this cell 

 I observed a small coloured blood corpuscle which had assumed a 

 cup-shape form, and which, for a short time, turned around its own 

 axis. Evidently this cell represented a colourless blood corpuscle, 

 which had accidentally adhered to the pus corpuscle, or perhaps 

 had sprung from it, in which case the body, as a whole, would have 

 represented a colourless blood corpuscle. It is diflScult, however 

 to give a satisfactory explanation of this phenomenon. 



