¥ 
h 
OcToBER 19, 1916] 
measure of State organisation for redepositing and 
cleaning the shell-tsh. Dr. Johnstone considered 
briefly some of the administrative problems involved. 
Dr, A. T. Masterman stated that in running sterile 
water mussels. will, in three hours, cleanse themselves 
of sewage organisms which have been introduced into 
their mantle cavity and. alimentary canal with food. 
Mussels may be relied upon to feed at night and at 
a suitably !ow temperature. It was found that 
chlorine in any form was not available as a direct 
sterilising agent, for its presence in the water in any 
appreciable quantity (0-5 per million) interfered with 
the normal functions of the mussel, and retarded the 
self-cleansing processes. Efficient sterilisation of sea- 
water can, however, be produced by the use of chlorine, 
and the following process of mussel purification has 
been devised at Conway by the Board of Agriculture 
and Fisheries. Into an upper tank river-water (80,000 
gallons) is pumped and allowed to settle, and the clean 
water is run into a lower tank, together with sufficient 
hypochlorite solution to produce an initial strength of 
three parts per million. 
effected overnight. In other still lower, shallow tanks 
mussels, which have been thoroughly washed, scoured, 
and picked over, are placed two deep on grids. The 
sterile water is then passed into the mussel tanks, its 
surplus of hypochlorite being removed during its 
passage by addition of sodium thiosulphate. The 
mussels remain in the sterile water for at least one 
night, and are then washed and hosed. They are left 
in sterile water for another night, and are then ready 
for packing. 
Dr. E. J. Allen referred to the account given by 
Prof. Herdman of the establishment of a fishery for 
sprats on the Lancashire coast, and expressed the hope 
that attempts would be made to establish in this 
country an ‘industry for preserving these fish in oil, as 
had been done on a large scale in Norway. He 
thought that a great deal more might te done in the 
way of preserving fish if the matter were properly 
organised. There were often gluts, when large quan- 
tities of fish were wasted which might well be saved 
and made available as food. 
In his account of the scales of fishes and their value 
as an aid to investigation Prof. Meek pointed out that 
it had been established by a wealth of observations 
that the physiological processes in fishes suffer a re- 
lapse in winter, and that the seasonal diminution in 
the rate of growth is recorded on the scales, as in 
other skeletal structures. This discovery has enabled 
investigators to state the rate of growth, the age-com- 
Sterilisation of the water is, 
position of samples, and other important correlated | 
facts. The method was illustrated by photographs of 
the scales of the herring, bass, and several Gadoids 
and Pleuronectids. 
Dr. Masterman stated that although the great 
majority of scales in a Gadoid fish, e.g. the haddock, 
show the same number of annual rings, it was possible 
to find a certain percentage with a smaller or greater 
number. In large samples’ of haddock from the 
Dogger Bank and other parts of the North Sea the 
scales showed evidence of active growth for two 
separate periods of the year, the explanation of which 
is obscure. In the salmon the determination of age 
is complicated by cessation of growth at certain 
periods, and also by destruction of the edge of the 
scale at spawning. As a general rule, the zones on 
the scales of fishes are an expression of variations in 
growth dependent upon seasonal changes, but the inter- 
pretation of individual cases is full of pitfalls. 
Dr. C. Jee reviewed the fluctuations of the 
herring, mackerel, and pilchard fisheries off the south- 
west coasts in the light of seasonal variations of hydro- 
graphical factors. The landings of herring, mainly at 
NO. 2451, VOL. 98] 
NATURE 
137 
Plymouth in- December, appear to be heavier in those 
years in which the sea-temperature is below the 
normal, but are also dependent in some way upon the 
preceding summer maximum, During the years 1904-11 
(inclusive) the landings of mackerel, which are 
caught chiefly in May, seem to be correlated with the 
sea-temperature of that month. For the years 1905-10 
(inclusive) the yields of the pilchard fishery fluctuated 
in the same manner as the magnitude of the seasonal 
salinity ranges. These are probable measures of the 
strength of the Atlantic current, which was therefore 
stronger in those seasons which were followed by a2 
more successful pilchard fishery. 
Fp IE 
BITTER PIT. 
HE disease of apples (and pears) known as bitter 
pit manifests itself externally by depressions of 
the surface of the fruit and internally by patches of 
discoloured and dead tissue. It is a disease which 
may make its appearance whilst the fruit still hangs 
on the tree, or it may declare itself in the fruit-room 
and even in cold storage. 
This disease has been, and still is, 
great loss to growers. Thus it has happened not 
infrequently that whole consignments of apples 
shipped from Australia to England have developed 
the disease so severely as to have become unsaleable. 
Hence it is not surprising that so progressive a com- 
munity as the Commonwealth of Australia should 
have instituted, with the co-operation of the State 
Governments, a special research into the nature of 
the disease, its remedy and prevention. This re- 
search, endowed for a period of four years, was 
entrusted to Prof. D. McAlpine, and the fourth and 
final report now issued testifies to the assiduity and 
thoroughness with which both Prof. McAlpine and 
his colleagues have prosecuted their inquiries. As 
is pointed out in the introduction to the report, when 
the investigations which it summarises were begun 
bitter pit was regarded as a mysterious disease. It 
is associated with the presence of no parasite, nor is 
it a consequence of puncture by insects of the skin 
of the fruit. wert had, it is true, advanced evidence 
in support of the view that bitter pit is a result of the 
local toxic action of copper-containing spray fluids. 
That hypothesis has not, however, met with general 
acceptance. 
Our knowledge of the ztiology of this disease being 
sO vague, we turn with interest and curiosity to learn 
the results of Prof. McAlpine’s inquiries; but it must 
be confessed that although we discover much valu- 
able and interesting information in this large and 
admirably illustrated volume, we fail to find the 
revelation of the mystery. The symptoms of the 
disease are described in detail; evidence is brought 
forward that severely pruned trees yield more pitted 
fruit than is produced by lightly pruned trees; that 
nitrogenous manures appear, albeit often to no con- 
siderable degree, to increase the pitting of fruit; that 
certain varieties are more resistant and certain others 
more susceptible to the disease—in fine, we learn 
much that is useful and suggestive, but of the cause 
or causes of bitter pit we are no wiser after than 
before the perusal of this monograph. We insist on 
this point with some emphasis because we think 
that it should have been made clear at the outset of 
the report, instead of which we find it there claimed 
that the research has been brought to a successful 
issue. 
1 “Ritter Pit Investigation. The Experimental Results in Relation to 
Bitter Pit, and a General Summary of the Investigation.” By D. McAlpine, 
appoi ted by the Commonwealth and State Governments of Australia. 
Fourth Report, rg9r4-15. Pp. 178+70 figures and coloured frontispiece. 
(Melbourne : The Government Printer.) 
the cause of 
