1888.] Dr Woodhead o% Mercuric Salts as Antiseptics. 249 
much more reliable than the bichloride of mercury. It may be 
used from the commencement, being changed from time to time as 
required, either alone or with Muller’s fluid, or it may be used to 
continue the preservation after the organ or piece of tissue has 
been placed in perchloride of mercury solution for the purpose of 
bringing about coagulation of the albuminoid materials. When 
used for this purpose, great care should be taken to change the fluid 
frequently, for a few days, if putrefaction has commenced in the 
slightest degree, whether the bichloride or the biniodide be used, 
otherwise the sulphuretted hydrogen developed is quite sufficient to 
render a great part if not the whole of the mercuric salt inert, as it 
is converted into the sulphide. After the putrefactive process has 
been checked, it is not necessary to change the fluid. 
In conclusion, I must thank my friends Drs Gibson, Stockman, 
and Edington for several valuable hints and corrections given 
during the time that I have been carrying out my experiments. 
3. The Effect of Differential Mass-Motion on the 
Permeability of a Gas. By Professor Tait. 
This will appear in the Transactions in Part III. of Prof. Tait’s 
paper ‘‘On the Foundations of the Kinetic Theory of Gases.” 
4. On a New Diffusiometer and other Apparatus for 
Liquid Diffusion. Part II. By J. J. Coleman, E.R.S.E., 
E.I.C., E.C.S. 
I had the honour of communicating to the Royal Society of 
Edinburgh, upon the 15th July last, a paper describing a new 
diffusiometer. This instrument wns devised to make visible to the 
eye the diffusion of acids or alkalies into a supernatant column of 
water. 
In ease of acids the column of wnter was made of a yellow 
colour by minute measured quantities of an alkali and methyl 
orange, and in case of alkalies the water was made acid and of a 
red colour by minute but measured quantities of an acid and 
methyl orange. The coloured water was placed in a tube resem- 
