Description of Plate. 



Photograph of a section of an udder injected through the teats 

 with a mixture of lampblack and gelatin. The gelatin is removed 

 from the teats and cisterns in order to show the lining mucous mem- 

 branes of those cavities. The jet black areas throughout the whole 

 section indicate the presence of the lactiferous ducts which com- 

 municate with the cisterns. The linest ramifications of those ducts, 

 almost invisible to the naked eye, are manifest by the darkening of 

 the cut surface exposed to view. 



278 



