370 The Ducts of the Human Submaxillary Gland 



yellow, cinnabar, or Prussian blue. Prussian blue is the best pigment 

 for this purpose as its dark color renders the smallest ramifications vis- 

 ible and its fine granulation often allows the mass to pass easily through 

 the intralobular ducts into the alveoli themselves. When it is desired 

 to inject only the sublobular or lobular ducts chrome j^ellow or cinna- 

 bar should be used, for such masses do not, as a rule, pass beyond these 

 structures into the finer ducts. Celluloid colored by victoria blue is a 

 good mass, its advantage lying in the fact that it can be kept in the air 

 as a dry preparation without shrinkage and does not have to be pre- 

 served in glycerine like the celloidin injections. For these corrosions 

 commercial celluloid dissolved in acetone can be used or the celluloid 

 may be made by adding camphor and acetone to celloidin. Apparently 

 the granular pigments do not give such good results with the celluloid 

 mass for the corrosion is liable to crumble after the surrounding tissue 

 has been destroyed. Both the celluloid and celloidin can be freed from 

 the glandular tissue surrounding them by the pepsin hydrochloric diges- 

 tion fluid or a more rapid destruction of the gland is easily effected 

 by immersing the injected organ in commercial hydrochloric acid. 

 Inasmuch as the ducts are small, the acid does not make the prepa- 

 rations too brittle to be handled. All of our injections have been 

 prepared in this way rather than by the use of the more tedious pepsin 

 method. The stereoscopic microscope proved to be of the greatest ser- 

 vice in the study of the corrosions. By its use we can follow, OAving 

 to its deep field, the course of the finer branches accurately in three 

 dimensions and get much sharper pictures of the relations of these 

 structures than by the old flat field microscope. 



By far the best way of showing duets in relation to the frame-work 

 of the glands is by a method devised by the writer " while working iu 

 the laboratory of Prof. Spalteholz in the Anatomical Institute of Leip- 

 'zig. Small blocks of tissues are hardened in the graded alcohols, 

 bichloride or Van Gehuchten's fluid, dehydrated and then repeatedly ex- 

 tracted with the (Soxhlet) apparatus and digested until all of the glan- 

 dular elements are dissolved and nothing but the frame-work remains. 

 ITp to this point this is the method of piece digestion devised by Spalte- 

 holz " for the demonstration of connective tissue in sections. After 

 the digestion is complete, the digested frame-work of the organ is then 

 cleared in glycerine, creosote or xylol and is then ready for preliminary 

 study. This block of tissue, owing to the fixation and hardening, retains 



2 Flint: Johns Hopkins Hospital Bulletin, Feb., 1903. 

 sSpalteholz: Arch. f. Anat. u. Pbys., Suppl. Bd., 1897. 



