BLOOD CELLS. 



679 



state of the nucleus, the particles of which were either 

 tending to unite with one another, or there was a sepa- 

 ration of the nucleus into several smaller portions. 

 Wharton Jones, however, says there is no subdivision of 

 the nucleus. 



If we examine a drop of blood under the microscope, 



Fig. 314. 



1, A portion of the web of a Prog's foot, spread out and slightly magnified to 

 show the distribution of the blood-vessels. 2, A portion magnified 250 dia- 

 meters, showing the ovoid form of the blood-discs in the vessel, beneath 

 which a layer of hexagonal nucleated epithelium-cells appear. 3, Human 

 blood discs, as they appear when fresh drawn (magnified 250 diameters). 



the corpuscles aggregate themselves together like rolls of 

 coins, fig. 314, No. 3, presenting a kind of network so 

 long as they remain suspended in their liquor sanguinis. 

 After the lapse of a few minutes, the fibrin, from its elasti- 

 city, contracts more and more, and a yellow fluid, called 

 serum, is pressed out, or, in other words, the components 

 of the liquor sanguinis, with exception of the fibrin, and 

 only a shrunken, jelly-like mass remains. 



The blood-corpuscles of the lower animals Mr. Gulliver 

 has especially studied. In the blood-corpuscles of birds, 



