Ilistogenesis of the Adipose Tissue. 435 



Appendix. 



Since receiving the page proof of this article I have discovered 

 that after formalin fixation, usually only a part and often none at 

 all of the fat-content of muscle fibers and epithelium can be stained 

 with Scarlet red, Sudan, or osmic acid. If the tissue be stained 

 fresh in the stains mentioned above, a considerable amount of fat 

 can be demonstrated in the muscle fibers of a number of animals 

 including the ox; but if the tissue be fixed in formalin a few days 

 it is often impossible to demonstrate any fat in this situation. I 

 have found that after a few days' fixation in formalin little or no 

 fat can be stained in the muscle fibers of the frog or chicken, and 

 with the exception of a few samples the same is true of the ox muscle 

 fibers. 



Mr. H. H. Bullard has recently prepared special concentrated 

 solutions of Scarlet red and Sudan which stain a great many more 

 droplets in muscle fibers and epithelium than are brought out by the 

 ordinary stains. We have not yet decided whether all the droplets 

 brought out by Eullard's stain are neutral fat, but it seems probable 

 that they are all of a fatty nature. 



The use of Bullard's stains on fresh material gives such splendid 

 pictures that it seems certain there must l)e a revision of all the work 

 that has been done on the fat-content of tissues both physiological 

 and pathological. 



In a short time papers will appear setting forth the results men- 

 tioned above. 



