Anatomy and Physiology. 63 



the ox from 0.02 to 0.03, in man from 0.01 to 0.02. Their 

 nuclei are in diameter from 0.005 to 0.008 millimetres. They 

 are sometimes round, sometimes flattened, and of a distinct 

 polygonal form in man. These facts sufficiently refute the 

 opinion of Dujardin and that of Guillot, according to whom, 

 the cellules are irregular particles, not limited by any envelope, 

 and of a consistence between fluid and solid. We have not 

 convinced ourselves of the fact advanced by Huschke, that 

 each cellule distributes a filament which connects it with the 

 biliary canalicle, and by which the bile escapes. 



The hepatic cellules when pressed against each other form 

 little islets surrounded by blood vessels. We owe the actual 

 state of our knowledge of the distribution of the blood vessels 

 of the liver, almost entirely to Kiernan. 



It is easy to convince ourselves of the existence of the capil- 

 laries, even without making injections, by examining with a 

 microscope that magnifies 100 to 150 times the free and 

 transparent edge of the liver of a small animal, for instance, a 

 duck or a mouse. In using a duck^s, we should use indivi- 

 duals whose livers are free from black pigment, and we should 

 avoid as much as possible all compression. Under these cir- 

 cumstances it is quite easy to recognise a very pretty net- 

 work of capillary vessels with distinct walls, and the hepatic 

 tissue placed in rounded off, or slightly polygonal meshes. On 

 tearing the preparation, we meet with very fine capillary ves- 

 sels, whose delicate structure agrees with that of the vessels of 

 other tissues, and is proportionate to their diameter. We 

 then frequently recognise the trunks of arteries or of veins, 

 the latter covered by pigment cellules, to which again are 

 appended the capillaries. Those who are not familar with the 

 use of the microscope, may best convince themselves of the 

 existence of those capillaries by previously injecting the 

 blood vessels with tincture of iodine. The capillaries are 

 then turned to a lively yellow, and are easily recognised 

 among the hepatic cellules. 



