150 THE AMERICAN MONTHLY [May, 



cells are thus shown not to be square in cross-section 

 as might be imagined, but five or six sided. They are 

 the form that would be produced on nearly equal yield- 

 ing cylinders, placed side, by mutual pressure. 



The outer coat of the small intestine is one of the best 

 objects for the study of unstriped muscle tissue. In sec- 

 tions of the organ the mode of association of the cells 

 can be determined after the separate fibres have been is- 

 olated and examined in specimens which have first been 

 macerated. The maceration in alcohol 30 per cent, 24 

 hours is suflicient for the purpose of separating the cells. 



trans . 



longi ludi nal. 



Unstriped muscular t i ssue,Smdl 1 Intestine. 



Figure 1 of the accompanying cut is in a single cell ac- 

 curately drawn with the camera lucida from such a prep- 

 aration. It is extremely long and slender, with a central 

 nucleus. Figures 2 and 3 are from the muscular coats in 

 an ordinary section of the small intestine, in the former 

 the nuclei are visible and the general parallelism of the 

 cells but a wrong idea of the length of the cells would 

 be derived from such an examination because the ends 

 are so slender that they are lost in the mass, the two 

 figures are drawn on exactly the same scale, and the nu- 

 clei if compared are seen to be alike in size. In a cross- 

 section the cells appear polygonal in outline, and their 

 nucleus is seen to occupy the centre of the cell, the rea- 

 son that no nucleus is seen in some of the cells as well 

 as that they are not all of the same size is because all 

 are not cut in the same level of the cell. 



The pancreas is closely similar to a salivary gland. 

 In general sections the ducts and their divisions are 

 shown as in the parotid, and the mass is composed of 



