ij6o Correspondence. [September, 
manufacture permanganate of soda at from £24 to £30 per ton. 
Any practical maker of permanganate will laugh at this notion. 
Soda is certainly cheaper than potash, but the Board will find 
that permanganate of soda is much more difficult to make than 
permanganate of potash, and that very much more than the 
theoretical quantity of alkali is required. 
But even were they to sueceed in obtaining the produCt at 
^24 per ton, and if the additional outlay did not exceed the 
modest £200 daily on which they calculate, we must remember 
that all this is pure waste — a simple addition to the heavy expense 
already going on. Not a farthing’s worth of any valuable matter 
will or can be recovered from the river ! 
In a sanitary point of view the Board are equally mistaken. 
To destroy all the putrescent and putrescible matter in water by 
means of permanganate, a very large quantity of the disinfectant 
must be used, and the mixture must be boiled ! Otherwise much 
of the organic matter escapes destruction, and quietly goes on 
putrefying, and the nuisance continues. We must also remem- 
ber that permanganate has, in the cold, very little aCtion on 
those minute living organisms which are now known to be the 
germs of infectious disease. I have seen such organisms retain 
their vitality for hours in water tinged a decided rose-colour 
with permanganate of potash. The same faCt was recorded by 
Mr. W. Crookes, F.R.S., in a communication to the British 
Association, as far back as 1866. In short, permanganate— 
though it may remove some of the products and the outward 
signs of putrefaction — leaves the cause of the mischief un- 
touched. 
Lastly, the addition of permanganate to water leaves it always 
in an alkaline condition,— the very state most favourable to 
putrefaction and to the increase of disease germs ! 
I can only wonder at the obstinacy with which the Board 
avoid the only feasible method of dealing with this evil, and at 
their ingenuity in devising futile expedients. 
Argus. 
STURGEONS. 
Are we to understand that the Shovel-nosed Sturgeon which 
“ exhibited on the surface no sign of eyes” was a normal or an 
abnormal specimen ? If normal, one would like to know more 
of its habits. I have a theory that the common sturgeon lives 
mainly on flatfish, such as skates and thornbacks, and that while 
its snout is for hunting them in the mud or along sand or gravel, 
its very powerful sucker is for seizing and devouring them while 
