402 Dr. H. Charlton Bastian on the Origin 
solution of chromic acid, when it was removed and placed in 
a bottle still wet with a 10 per cent. solution of formalin. 
The screw-top having been fixed so as to prevent evapora- 
tion, the bottle was transferred to an incubator and left at a 
temperature of 76° F. for thirty-six hours *. When the 
organ was cut the chromic acid was found to have discoloured 
it to a depth of about a quarter of an inch, but within that 
margin the kidney-substance was red and only slightly 
softer than natural. There was no distinct odour of putre- 
faction. A small portion of the organ was cut out and 
teazed in a drop of a weak solution of gentian-violet, and 
fragments, after a short. interval, were carefully examined 
under the microscope. A comparatively small number of 
Bacteria were found free, between the separated and broken 
up cells, and the ceils were densely filled with granular 
matter, as may be seen in Pl. XXVI. fig. 10, A (x 700), 
but it was impossible to identify with certainty any of the 
granules as germs of Bacteria. Sections that were made 
and carefully stained gave no more definite results. 
Another sheep’s kidney from a freshly killed animal was 
therefore obtained and treated in the same manner, except 
that it was left in the incubator at 76° F. for three and a half 
days. When the organ was cut through it was deeply 
stained at the circumference as before with the chromic acid ; 
but the red tissue within was much softer, and the odour was 
most offensive and putrid. Portions of the organ were at 
once put into a 10 per cent. formalin solution with a view 
to obtaining sections therefrom, but a minute portion was cut 
off as before and teazed in a drop of gentian-violet. On 
examination with the microscope after a brief interval I found 
the fragments of the tubules and kidney-cells full of Micro- 
cocci which had taken the stain well, together with numbers 
of figure-of-eight organisms and short chains (Streptococci) 
such as are shown in Pl. XXVI. fig. 10, B (x 700). 
In a few days Dr. J. S. Collier kindly sent me a number 
of sections, stained and unstained, which he had been good 
enough to cut from the portion of the kidney in the formalin 
solution which I had handed over to him. Some of the 
specimens sent to me had been stained with methylene-blue 
or with logwood, and then mounted in balsam; while I 
stained some of the plain sections with gentian-violet, and 
subsequently mounted them in glycerine. On the whole, 
rather more details could be made out with these latter 
sections than with the specimens mounted in balsam. 
* I was using the incubator for other purposes at this temperature, 
and therefore did not alter it. 
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