JUNE 3, 1915] 
NATURE 
373 

Towards the end of the article, the author deals 
with the influence of vitamines, and indicates that, 
while these substances are present in butter, they 
would not be met with in margarine. 
This characteristic would meet the case as regards 
certain butter and margarine products, but by far the 
Jargest quantities of butter now. on the market are 
made from pasteurised cream, and the pasteurisation 
would no doubt have reduced the original quantities 
of vitamines very considerably. 
On the other hand, large quantities of margarine 
contain, among other fats, cold-pressed oils (such as 
ground-nut oil) which, like the better grades of olive 
oil, do not undergo any refining process whatever, 
and would theretore lend to the margarine their 
original content of vitamines. 
If vitamines are produced in the lactic acid fer- 
mentation of milk, an abundance of these precious 
substances would be imparted to both butter and mar- 
garine, as in buttermaking the ripening takes place 
after the cream has been pasteurised, and in the 
manufacture of margarine the ripened skim milk is 
churned with the fat after the latter has been refined. 
Hence in both cases the vitamines produced in the 
fermentation process are not subsequently subjected 
to any harmful treatment. 
It therefore appears that, so far as the presence or 
absence of vitamines is concerned, margarine would 
rank as equal to butter. There are, in fact, qualities 
of margarine on the market which contain a small 
proportion of fresh egg yolk, and such qualities would | 
doubtless be of high standing as regards vitamines. 
B. 

So little is at present known about vitamines that 
~S. H. B.” may well be correct in assuming their 
presence in cold-pressed oils, in ripened skim milk, 
and in fresh egg yolk. Even hot-pressed oils have 
probably not been subjected to such a temperature 
as to kill the vitamines. 
On the other hand, if the present writer’s memory 
is not at fault, the work of American investigators 
has shown that of several oils investigated, butter 
fat alone contained vitamines. There is also evidence 
to indicate that vitamines are closely associated with 
lipoids, and it is doubtful whether they would be 
formed during lactic fermentation. It is evident 
should vitamines be present in nut oils as suggested, 
that nuts might form a valuable preventative of beri- 
beri, or scurvy; the writer is unaware if this has been 
tested in practice. 
As stated in the original article, probably sufficient 
vitamines are present in the rest of the dietary to 
enable them to be dispensed with in the fat. 
THe WRITER OF THE ARTICLE. 
May 20. 

THE EXTINCTEUR AND ITS 
LIMITATIONS. 
| Raee portable chemical fire-extinguisher, better 
known as extincteur, has been much before 
the public of late. Leaving aside the whole of 
those unfortunate appliances that belong to the 
dry powder class and the glass hand grenade 
type, which are entirely untrustworthy, the port- 
able chemical fire-extinguisher in modern practice 
may be looked upon as a cylinder of from 2 to 
3 gallons’ capacity, containing water, with the 
addition of some substance which may, or may 
not, add to the efficiency of the extinguishing 
power of the water discharged. 
NO. 2379, VOL. 95| 


| pressed air or the like, 
‘There are, of course, one or two other forms 
of portable chemical liquid fire-extinguishers, 1.e., 
certain forms of less than a gallon capacity con- 
taining carbon tetrachloride or some combination 
thereof, intended for use on small petrol fires, 
and where the capacity is sufficient, say, from 
2. quarts to 1 gallon, and the chemical is dis- 
charged automatically by some capsule of com- 
effective results are ob- 
tained from such appliances on small spirit fires. 
| Where, however, the appliance only has the capa- 
city of a pint or quart of carbon tetrachloride 
or some combination thereof, and has to be 
applied by manual action, the limit of effective- 
ness is certainly very small, a quart of chemical 
applied, say, by a double action squirt being able 
to deal at the most with a 2 gallon tin of petrol 
spilt over a motor-car or in some vessel of no 
great area. A weak spot in the use of carbon 
tetrachloride and its combinations, by the bye, 
is the fumes it gives off when in contact with 
fire. For this reason its use in enclosed spaces 
should in any case be avoided, and people suffer- 
ing from liver complaint should in any case keep 
clear of this chemical when used on fires. 
But to revert to the ordinary portable chemical 
liquid extinguisher of 2 to 3 gallons’ capacity, 
as seen in many public buildings, and thus con- 
sidered by the general public as something ac- 
ceptable for every-day purposes. We are desirous 
of warning the public as to unsuitable purchases 
of such appliances. To begin with, in a very 
general way a portable liquid chemical fire-extin- 
guisher is not the alpha and omega of first-aid 
fire-extinguishing, although there is no doubt that 
these appliances as such are popular. They look 
so bright and neat. Their presence advertises 
the owner’s forethought. If finished on copper 
they are quite ornamental. 
For the ordinary householder and for the ordin- 
ary business establishment where fire appliances 
are not under constant inspection, we would, 
however, rather pin our faith in the ordinary 
bucket of water energetically applied, and the 
ordinary miniature manual hand-pump or corrido+ 
engine. A few dozen buckets and a couple of 
hand-pumps, involving together perhaps an ex- 
penditure of 5l. to él. will work wonders in a 
quite substantial fire, whilst the same 61. will only 
produce three or four 2-gallon extinguishers, 
which require, as a rule, ‘practice to discharge 
properly and time to re- -charge at intervals; they 
require also most careful maintenance, and at 
the best will give the user some 6 or 8 gallons of 
chemically prepared water as against, say, the 
50 gallons of water immediately available for con- 
tinuous application and rapidly replenished with- 
out intervals. A small stirrup hand-pump of the 
London type, by the bye, can be worked single- 
handed to supply 4 to 5 gallons per minute at 
an effective range of 25 to qo ft. 
The whole principle of putting out a small fire 
is the cooling effect of water applied in fair bulk 
continuously “and under pressure; and the cooling 
effect can be best obtained by a copious supply 
