GoDDARD, A Neiv Brain Microtome. 213 



of warping) into which is welded an edge of finest razor steel. 

 It is without flaw and is a model of accurate workmanship. 



After two years use, this microtome continues to be satis- 

 factory. Were we to make another machine now, only two 

 variations from the foregoing description would be made. It 

 would in no way be a detriment to have the blade thicker on 

 the back — one inch or even an inch and an eighth. It would 

 probably be an advantage in the matter of keeping it sharp — 

 the edge not being quite so thin would not nick as easily. Sec- 

 ondly, the supporting frame might be somewhat heavier. There 

 is a slight vibration, which, while of no inconvenience as yet, 

 may in time have some effect upon the delicacy of the adjust- 

 ments. 



The writer is very largely indebted to Dr. C. F. Hodge, 

 at whose suggestion the work was undertaken, for constant help 

 and suggestion in designing the machine, as well as valuable 

 aid in bringing out the completed microtome. 



West Chester, Pa., December Fourth, iSgg. 



EXPLANATION OF PLATES. 

 PLATE XIX. Figs. I and 2. 



Two views of the machine with brain in place ready for sectioning. 



A. — Blade, with pan attached, filled with alcohol. 



B. — Brain in position for cutting. 



C. — Wood fiber upon which brain is mounted. 



D. — Inner " box " which is raised and lowered by micrometer screw I. 



E. — Outer case which slides on the track F. (Fig. 2.) 



y^.— Track. (Fig. 2.) 



G. — Rack and pinion for moving carriage along F. 



H. — Graduated head of micrometer screw. 



/. — Micrometer screw. (Fig. i.) 



K. — Clicking attachment. (Fig. 2.) 



PLATE XX. 



Fig. 3. Shows a sagittal section of the brain about 100 //thick cut on 

 this microtome, and reproduced in the following manner : The unstained sec- 

 tion mounted in gum glycerine was printed directly onto velox paper, the paper 

 being put into the plate holder and exposed through the camera like a plate. 

 The mounted section was set up in front of the camera with the blue sky for 

 background. Finer details of course do not come out in the reproduction, al- 

 though they are beautifully shown in the section. The photograph is reduced 

 to about y-i^ natural size. 



