APRIL 30, 1914] 
NATURE 
221 
ing to show a steady increase,. while the receipts for 
admission at the gates of the gardens were the highest 
on record. The year will’ be notable for the com- 
mencement of the ‘‘ Mappin Terraces”’ in the gardens, 
now nearing completion, and also for the preparation 
and acceptance of a general plan, made under expert 
advice, for improvements in the arrangement of. the 
gardens as a whole. These alterations, which have 
become imperative owing to the increasing popularity 
of the gardens, will involve the abolition of the old bear- 
terrace, which, although one of the landmarks of the 
gardens, is now hopelessly antiquated and out of date. 
It is satisfactory to learn that plans for new and 
up-to-date salt- and fresh-water aquaria are under 
consideration. Neither has the scientific side of. the 
society’s work been neglected, special attention being 
directed in the report to the society’s share in the new 
mammal survey of British India, which has already 
resulted in the discovery of one new genus and 
several new species of rodents. 
oe 
In the twenty-seventh annual report of the Marine 
Biological Station at Port Erin, Prof. B. Moore and 
his co-workers have summarised important observa- 
tions on the hydrogen-ion concentration of sea-water, 
determining its degree of alkalinity or acidity, which 
does not remain: constant throughout the year but 
varies with the relative activities of vegetable and 
animal organisms, and acts as an index to these 
activities. There are two maxima of alkalinity corre- 
sponding to the two seasonal outbursts of diatoms. 
The change observed indicates a synthesis, at. these 
seasons, of some tons per acre of sea-water of organic 
vegetable matter for the nutrition of the . animals. 
The green plants or diatoms break up the bicarbonates 
present in sea-water and form = organic © com- 
pounds, the amount of the removal of the carbon 
dioxide being shown by the increase in ‘alkalinity in 
the water. It is noteworthy that the spring increase 
in alkalinity is just of the grade formerly found to be 
most favourable to the rapidity of cleavage in the 
initial stages of development of the eggs of the sea- 
urchin (Echinus). 
A RECENT issue of the Naturwissenschaftliche 
Wochenschrift (March 15, 1914) contains an 
article by Dr. F. Stellwaag, of Erlangen, in 
which he directs attention to the apparently 
contradictory results obtained by various observers 
who have experimented on the colour-sense_ of 
bees. Following the methods of Lord Avebury and 
of Forel, von Dobkiewicz came to the conclusion that 
bees are able to distinguish between colours, but 
are only attracted by them when they have learnt by 
experience to associate a given colour with the presence 
of honey. This he considers to accord with the fact 
remarked by Plateau that many colourless and_ in- 
conspicuous flowers are eagerly sought after by bees, 
while many brightly-coloured flowers are unvisited by 
them. These results were to some extent confirmed by 
von Frisch, who concluded further that the colour- 
vision of bees must resemble that of ‘‘red-blind ’’ men. 
Hess, however, disputes the conclusions of both pre- 
ceding experimenters, and considers that bees show 
no indication of being otherwise than totally colour- 
NO. 2322, VOL. 93| 
blind. Stellwaag himself is of opinion that in all these 
experiments an important factor has been overlooked, 
viz. the condition of the bees with regard to the general 
supply of provender. When this is deficient, bees will 
seek it anywhere. 
An interesting paper has been issued by W. E.' 
Castle and J. C. Phillips in Publication No. 195 of 
the Carnegie Institution of Washington (1914), on 
the effects of selection in modifying the pattern of 
piebald rats. The. piebald or ‘‘hooded”’ pattern be- 
haves as a Mendelian recessive to. the - self-coloured 
condition, but within the hooded class there is con- 
siderable variation in the extent of the coloured areas. 
The authors have made continuous selection experi- 
ments, both in the direction of greater and of less 
pigmentation, extending over thirteen generations 
and involving. the breeding of some 25,000 rats. 
Although the hooded pattern behaves as a Mendelian 
unit, selection of either plus or minus - variation 
brought about permanent changes extending far 
beyond the original variation of the race.. In each 
generation the offspring of selected parents tended to 
regress towards the mean of the preceding generation, 
with the result that when, after several generations 
of selection, the selection was reversed, the regression 
was away from the original mean. But by continued 
reversed selection from a race which had become very 
divergent, the mean was brought back nearly to the 
original starting point. Results are described of 
crosses between extreme plus and minus strains, and 
between such strains and self-coloured types. An 
account is also given of an extreme variant which 
appeared as a mutation. The paper shouid be com- 
pared with the recent work of Hagedoorn (Zeitsch. 
indukt. Abstam., xi., 1914, p. 145). . 
A DETAILED account of the twelve months’ poultry 
laying competition at the Harper Adams Agricultural 
College is given in the report of the college for 1913. 
Upwards of six hundred birds were tested, the average 
egg production being 152 for the twelve months 
period. A comparison of the returns obtainable from 
one acre of grass land when stocked entirely with 
poultry and the same area used for milk production, 
shows that a much greater return per acre can be 
produced in the former case, these being respectively 
41l. 13s. 4d. and 4l. 3s. 23d. It must be borne in 
mind that, although the gross return per acre in the 
case of the poultry is so much greater than for cattle, 
the expenses, capital and depreciation of stock, would 
be correspondingly high. Unfortunately, there seem 
to be no available figures which might be utilised for 
purposes of comparison. That the possibilities of eg¢ 
production on commercial lines are great cannot be 
denied, and the actual determination of these, and 
the factors which govern such production, should 
prove an interesting and profitable field for further 
investigation. 
A REPORT On sugar Cane experiments in the Leeward 
{slands which has just been published, contains a 
summary of the varietal trials and work on manuring 
conducted during the last few years. Of the varieties 
which have been under cultivation for some consider 
able time, and of which the relative merits and suita 
