6 6 THE AMERICAN MONTHLY [Mar., 



nuclear details, will find that alcoliol properly used will 

 give, in a majority of tissues and especially in glandular 

 tissues, entire satisfaction. The tissue should be placed, 

 as soon as possible after removal from a recently killed 

 animal, in ten times its bulk of thirty per cent alcohol, 

 after an hour it should be changed to the same ratio of 

 bulk of fifty per cent alcohol, after another hour it should 

 then be transferred to seventy per cent alcohol. It should 

 be cut into small pieces before the alcohol treatment, into 

 blocks of half an inch on a side, and should be changed 

 from the seventy per cent alcohol after twenty-four hours 

 to another bath of the same strength. It will then keep 

 indefinitely or can be imbedded and cut at once. Stain- 

 ing in bulk and imbedding by either the celloidiue or tlie 

 jiaraffine method and cutting and mounting are performed 

 in the usual way. 



The liver of a cat. — The liver furnishes a very good 

 example with which to begin in the study of the cellular 

 structure of an organ. As a whole the organ lies in the 

 anterior, or in man the upper, part of the abdominal cav- 

 ity. It is a large dark structure just above the stomach 

 and just beneath the diaphragm. In a recently killed 

 animal, as it is cut, a large amount of very dark " venous " 

 blood fiows from the cut surface. Its anatomy is too fa- 

 miliar to re(i[uire more than the merest summary. A 

 great duct runs from the organ into the small intestine, 

 thi» is the "common bile-duct, it comes directly from the 

 " gall-bladder '^ but indirectly from a multitude of lesser 

 ducts which lie in the areas between the "lobules" of 

 which the mass of the organ is composed, [see Fig. 1, P. 

 en] in a passage called the "portal canal." This same 

 l)assage between the lobules is the location also of arte- 

 ries and veins, [cf. Fig. 5J. Besides the "bile-duct" 

 which is an outlet passage for the secretion of the organ, 

 there are also two sets of blood-vessels which enter the 

 organ on its posterior side, these are the " Hepatic Ar- 



