140 The Microscope. 



TO PREPARE AMCEBOID CELLS IN THE INTESTINE. 



V. A. LATHAM, F. R. M. S. (lOND.) 

 ABSORPTION. 



|~^0 study the process of fat absorption, kill an animal three or 

 -*- four houi-s after feeding it with fat meat, or a frog two or 



three days after feeding with lard. Put a very small shred of the 

 mucous membrane of the intestine into 



(i) 1 ^ solution of osmic acid; or, 



(u) A mixture of this with alcohol. 



{in) ^ fo solution of chromic acid, mix with osmic acid in 

 variable proportion. 



{iv) Absolute alcohol. 

 For maceration with a view to separation of the tissue elements? 

 a mixture of glycerine, alcohol and ether in equal parts is employed, 

 afterwards the cells are fixed and stained by a few hours immersion 

 in ^-^j fo solution of chromic acid made with sodium chloride instead 

 of water, with or without the addition of a little osmic acid. After 

 forty-eight hours maceration the tissue elements are easily isolated 

 in large numbers, by simply tapping upon the cover glass after par- 

 tially separating by teasing with needles. For preparation of 

 sections either the freezing method has been adopted, or pieces of 

 tissue (sometimes after further staining with haematoxylin) have 

 been dehydrated with absolute alcohol and after being passed 

 through turpentine have been soaked with paraffin, cut with the 

 microtome and the sections mounted, by creosote-shellac method, 

 in Canada balsam. 



Examine tissue fresh, after being rapidly teased in sodium 

 chloride or serum. Transfer some specimens to dilute Kleinenbergs' 

 solution, and when stained thi'oughout, embed in cacao-butter 

 process ; afterwards extract all the embedding agent from them by 

 warm oil of cloves, first in spirit, and then in water, and finally 

 mount in glycerine. 



In the teased preparations in osmic acid and senim, many colum- 

 nar epithelial cells contain fatty globules stained black by osmic acid, 

 also in the numerous lymphoid corpuscles which are set fi'ee from the 

 retiform tissue of the mucous membrane by teasing. Hence it may 

 be inferred that the fatty matters are first taken up fi-om the cavity 

 of the intestine by the columnar epithelial cells; that they are then 

 transmitted in some ^way from these to the amoeboid lymph cells, 



