246 Proceedings of Royal Society of Edinburgh, [march 19, 
of potassium alone had been used was in the best condition. It 
appeared to be absolutely free from any change, in marked contrast 
to the bichloride specimen above mentioned. 
When sodium phosphate had been used, we had the most marked 
changes in the whole series. Although no penicillium was growing, 
the fluid appeared to be swarming with micro-organisms, espe- 
cially near the surface, and the odour coming from the fluid was 
very pronounced. On microscopic examination, micrococci and 
Bacterium termo were found in great numbers, and in a state of 
great activity. Penicillium and micro-organisms were also found 
in the mixture of biniodide, blood, and hydrochloric acid, and in 
this instance, too, the smell was somewhat offensive. The control 
experimental jar with the distilled water and blood was found to be 
swarming with micro-organisms, and the smell was very strong indeed. 
A few of the more important deductions to be drawn from 
the above observations, may be here briefly summarised. All 
observers refer to the fact that in experiments with antiseptics 
made on micro-organisms cultivated in fluid media, the results are 
never so satisfactory as when the organisms are cultivated on solid 
media, such as gelatine or agar agar. No doubt, the greater vitality 
of organisms so cultivated may have something to do with these 
results, but it must also be borne in mind that phosphate of soda 
is almost invariably one of the ingredients of a cultivating fluid, 
and we have seen that wherever it is present some micro-organisms 
flourish in spite of the presence of either bichloride or biniodide 
of mercury. The conflicting results of various observers are only to 
be explained by taking such factors into consideration. 
Klein’s and Law’s observations, though interpreted by them in 
different ways, may in all probability be brought under the same 
heading ; and it appears to be possible that Klein’s lower results, as 
compared with those of Koch, in the use of bichloride of mercury 
as an antiseptic, may have some such explanation as the following: — 
The peptones, like other albuminoids, are coagulable by bichloride 
of mercury ; hence a large proportion of the salt may be rendered 
completely inactive. It may be pointed out that, in Klein’s experi- 
ments, a single drop of the fluid in which the micro-organisms had 
been cultivated was drawn into a pipette, and then 100 drops (or 
these proportions) of the sublimate solution. It will be evident 
