1130 General Notes. [Dec. 
MICROSCOPY: 
Method of Photographing Serial Sections.—The develop- 
ment of microtomical technique has made it a comparatively 
easy matter to produce great numbers of fine sections in a very 
short time. As the sections with which an anatomist or an 
embryologist has to deal are generally too small for macro- 
scopical examination, it is often difficult to obtain an outlook 
over the material accumulated. The microscopical examination 
of hundreds or thousands of serial sections, if only for the pur- 
pose of general orientation, is a slow and tedious work. One 
cannot carry the asta of the series along while examining the 
sections, one by with the microscope. This can only be 
accomplished indirectly, through representations enlarged just 
enough to make it easy to examine them macroscopically. To 
make outline sketches of the whole series, or at least of the 
more important portions of it, calls for an enormous sacrifice of 
time, together with a large amount of most fatiguing mechani 
labor. Much more satisfactory results may be obtained by the 
st A photography, and with relatively little expenditure of time 
an 
Professor His? of Leipzig, to whom we are indebted for the 
“embryograph” ‘and a method of “ plastic reconstruction,’ ’ previ- 
ously described in this journal, employs the apparatus seen in 
the accompanying cut for photographing serial sections. 
The objective (Ob) is a Steinheil avtplanatic of 12 cm. focal 
distance, or an aplanatic of the same factory of 14 cm. focal dis- 
tance, The latter gives a little less light than the former, but 
pae the advantage of an accurate and uniformly-sharp 
-definitio 
For embryos that are not exceptionally small, a naa 
of ten to fifteen diameters generally suffices. Wit me 
fication not exceeding twenty diameters all the jeo moun 
time, Long series of sections can thus be photograp 
teni ee etek” of every kin 
projec tion-apparatus consists of a horizontal rack any 
ing at the anterior end a plate with the photographic obje on), 
- (Ob); behind this a second plate (C) (with a central perfo 2 eae 
connected with the first by a bellows, and servi aE 
for the object-slide; then a double banae i 
diameter, with a focal distance of 8 cm.; an 
argand gas-burner (B). 
* Edited by C. O. W ee, Wisconsin. soe 
a iat Ueber das Photographiren von S pert ittreihen ;” Arch. La. 
_ Phys., Anat. Abth., 1887, 2d and 3d Heft, p. 1 
sai in 
hind d all, an 
