THE LACHRYMAL GLAND 221 



Xr. TI^XJHNIQUE 



I. For the study of the gross characteristics of the gland, 

 calves' heads were embalmed by injecting, under pressure, into 

 the carotid arteries equal parts of glycerine, 95 per cent alcohol, 

 and carbolic acid full strength. A suspension of red lead, starch 

 and hot water was then injected, shortly after which dissection 

 of the orbit was begun. 



II. For the study of the ducts and their ramifications the 

 following methods were used : 



1. Flint C02), Spalteholz ('97). 



2. Injection method, see Hiiber's technique given in American 

 Journal of Anatomy, vol. (i, 1907, The Arteriolae Rectae of the 

 Alammalian Kidney. The celluloid mass withstood the corrosion 

 much better than the celloidin. Total peptic digestion required 

 on the average two weeks. 



3. Vital staining method with pyronin (See VI, 1). 



4. Kopsch ('10) — Golgi chrome silver method (somewhat 

 modified) for the demonstration of lumina of tubules and secre- 

 tion capillaries. 



III. For the study of the connective tissue framework. 



1. Flint, Spalteholz — After complete digestion, tissues were 

 imbedded in paraffin and thin sections made. 



2. Mall's method ('96) for the demonstration of reticulum with 

 frozen sections (25m). 



3. Tissues fixed in 70 per cent alcohol, imbedded in celloidin, 

 sections 10 to 20^ thick, fastened on slides, and digested and 

 stained by Mall's method were especially useful for the study 

 of the framework. The method (Jeffrey's) was as follows: 

 Sections were placed in a mixture of equal parts of glycerine and 

 95 per cent alcohol for some time before mounting. A thin 

 coating of Mayer's albumin was applied to clean slide, to which 

 section was transferred. A piece of smooth writing paper was 

 placed on the section and over this several layers of blotting 

 paper. A second slide was prepared in the same manner and 

 the two were bound tightly together with the blotting paper in 

 the middle. This was placed in a thermostat 60° C. for one-half 

 hour after which the slides freed from the paper. The slides 



