214 



HISTOLOGY 



vibrate in the current. This fluid thus acts as the intermediate sub- 

 stance. 



It is possible that the purely static function with reference to gravity 



is performed by other sensory 

 areas in the larger cavities of 

 the sacculus. Here, particles 

 of lime act as the intermedi- 

 ate substance instead of a 

 fluid, as in the ampulla, or a 



it 



cuticular structure, as in the 

 cochlea. Figure 194 repre- 

 sents a nitrate of silver prep- 

 aration from the mouse to 

 show the nerve distribution in 



\/ 

 sen. c. 



nv.f: 



FIG. 194. Portion of macula acustica sacculi of SUch a Sensory region of the 



mouse, treated by Golgi's method to show nerve- ventriculus. This region is 



ending on sensory cells (sen.c.). b.m.. basement , 7 .. 



membrane; sup.nu., nuclei supporting cells; nv.f., known as a MOCUlar OCUStlCd, 



nerve fiber. (After VON LENHOSSEK.) and its cells greatly resemble 



those of the ampulla ridge. 



Technic. To have a complete understanding of a static organ, it is 

 necessary to have a great variety of preparations. The finer anatomical 

 relations must be studied, and these can best be got, in most cases, by 

 well-prepared serial sections. Such series are difficult to prepare on 

 account of the heterogeneous tissues that go to form these organs. In 

 the cases of the higher animals, various bones, cartilages, and otoliths 

 have to be dealt with as well as many grades of connective tissues. A 

 decalcifying fixative should be used in these cases, and care should be 

 taken not to render the remaining connective tissues unduly hard and 

 brittle. Zenker's fluid and chrom-aceto-formal were very successfully 

 used, sometimes followed by a double embedding in paraffin and cel- 

 loidin. When it was desired to stain before sectioning, a saturated solu- 

 tion of sublimate with 5 per cent of acetic acid was used to fix. Silver 

 and methylene blue are essential in making a study of the nerve elements. 

 The writers also found that carefully teased specimens that had been 

 macerated somewhat were invaluable in class demonstrations. This 

 latter method was modified as follows to form a valuable process in the 

 study of any epithelia. The tissue was first placed in a macerating 

 medium that was at the same time a fairly good fixative; weak osmic 

 and chromic acids, as ordinarily used to macerate, were found to be the 

 best, and one third alcohol also gave good results. The tissue was 

 handled with the greatest caution, and somewhat before it was macerated 

 enough to tease, it was washed, stained, dehydrated, and embedded in 

 paraffin. Sections of rather greater thickness than usual were then 



