THE MICROSCOPE. 219 
more difficult to get a satisfactory measurement of a dry grain, as it 
may be partly collapsed or the light so broken that no distinct out- 
line is seen. It seems evident therefore that the full and perfect 
measurement of a pollen grain requires that it be taken twice; once 
when dry, that is, in the condition when ready for passage from 
dehisced anther to stigma, and again when fully swollen by 
imbibition of water, and both figures should be given with con- 
ditions for each. 
MICROSCOPY.* 
Movntine Freso Water Ate.t—Klein uses Migula’s process. 
A drop of one per cent. osmic acid is run under the cover-glass and in 
ten to twenty minutes afterwards glycerin is added. In order not to 
blacken the oil drops, ete., the osmic acid is added in as small 
quantities as possible, and this is best done by blowing it under the 
cover-glass through a capillary tube. In all other cases the author 
uses glycerin-gelatin, which with the proper precautions, is an 
excellent embedding material. The object is first hardened by 
exposing it as a hanging drop to the fumes of the acid for a few 
minutes. It is then placed in one or two drops of dilute glycerine, 
and the surplus having been drained off or the water evaporated, 
a drop of glycerin-gelatin, previously heated in a test tube, is 
dropped on by. means of a fine glass tube. By this device air 
bubbles are avoided. 
PATHOLOGY. ¢ 
Ertotocy or Diprurueria.—If we compare the streptococcus 
diptherize with those species of bacteria already known and fully 
described, we find that, in its form and in its modes of growth, as 
well as in its effects when injected beneath the skin or into the blood 
of animals, is appears to be identical with two well-known species, 
called streptococcus pyogenes, and streptococcus erysipelatos. I 
have carried the cultures of streptococci from cases of diptheria, 
along side by side with cultures of streptococci made from various 
cases of simple acute erysipelas, and simple phlegmonous inflamma- 
tion, week after week. Over and over again I have stained, 
measured and compared the growth from these three sets of sources, 
I have repeatedly inoculated duplicate sets of animals with the 
*Under this heading will be included descriptions of New Instruments, Microscopical 
Manipulations, Stains and Re-agents, Photomicrography, etc. 
+R. M. Jour. from Hedwigia, 1888, pp. 121-6. 
_  #tUnder this heading will be included all Abstracts relating to the Histology of 
Diseased Tissues, both Animal and Vegetable. 
