300 
NATURE 
[| DECEMBER: 14, 1916 
ploration of the deep-sea fauna. We can speak from 
personal experience of the efficacy of a modification of 
Dr. Hansen’s methods which has been used with 
great success in the exploration of the deep water to 
the west of Ireland, whete the use of fine silk tow- 
nets attached to the dredge and trawl] has revealed 
a’ wealth of species undreamt of by earlier British 
marine biologists. 
Dr. Hansen prefaces his reports by a critical account 
of the literature relative to the area surveyed by the 
Ingolf, and a valuable summary of the geographical 
and bathymetric distribution of the species in the 
collection. 
Of special interest is his conclusion that the Wyville- 
Thomson ridge does not form an absolute line of 
‘separation between the deep-sea fauna of the cold and 
warm areas. Evidence is submitted of several species 
which have been found in both areas, and the author 
rejects the hitherto accepted explanation of this dis- 
tribution, that these species were taken pelagically 
and not actually on the bottom. 
Dr. Hansen has a valuable chapter on sexual differ- 
ences among Tanaidz, in which he comments on the 
rarity of adult males, and makes the interesting sug- 
gestion fhat the development of the marsupium and 
eggs in the female is accompanied by a reduction in 
size. His remarks on the nomenclature of segments 
and joints and on generic and specific characters in 
Tanaids will prove of the utmost service to students 
of this difficult order of Crustacea, which is marked 
by great uniformity of external form and the absence 
of tangible characters upon which species and genera 
may be distinguished. 
~The most important morphological feature brought 
forward in these reports is the evidence in favour of 
the author’s theory, advanced some twenty-three years 
ago, that the sympod of all biramous appendages in 
‘Crustacea was primarily three-jointed. Hitherto no 
evidence in support of his case could be brought for- 
ward as regards the thoracic limbs of the Malacostraca 
(with the exception of Nebalia), but Dr. Hansen has 
now produced evidence of the existence of a przcoxal 
joint in the maxillipeds of two species of Isopoda. 
The new species and genera are clearly described 
and illustrated by a series of beautifully drawn figures. 
The wealth of material at the disposal of the writer 
and his clear and critical insight into the true value 
of characters for systematic purposes have led him to 
suggest several modifications in the minor classifica- 
tion of the families and genera of Isopoda, which tend 
to a better understanding of the group and to a restora- 
tion of order out of the chaos into which it was rapidly 
falling. 
Students of Arthropoda have been indebted to Dr. 
Hansen in the past for a series of illuminating papers 
elucidating the structure and classification of many 
obscure and difficult groups. Their obligations are 
considerably increased by the publication of these 
valuable papers, which workers on Isopoda will find 
indispensable to the successful prosecution of their 
studies. W. M. T. 
GROWTH FACTORS OF FOODS. 
HE Biochemical Journal more than maintains its 
increasing and well-deserved reputation in the 
‘current number (vol. x., No, 3). The articles of most 
general interest are two on feeding experiments, which 
were carried out at the Cambridge Biochemical Labora- 
tory under Prof. F. G. Hopkins’s direction. These 
experiments are a continuation of the very careful and 
elaborate series which Prof. Hopkins has been making 
for several years past upon the growth factors of foods. 
In all of them young albino rats of uniform origin, 
NO. 2459, VoL. 98] 
sex, and weight are employed. They are fed and 
treated in an exactly similar manner, ex with | 
regard to the essential factor with which the investiga- 
tion is concerned. The food consists of starch, cane- 
sugar, fat, suitable salts, and various protein products, ~ 
together with the alcoholic extract of 1-5 c.c. of milk 
per diem, as this extract contains an unknown ‘“‘vita- 
mine,’ which is absolutely essential for the normal 
growth of the rats. In the first series of experiments, 
carried out by G. Totani, it was found that rats fed on 
the hydrolysed products of caseinogen from which all 
but o-2 per cent. of the tyrosine had been removed, and 
to which a small quantity of tryptophane kad been. 
added, grew just as rapidly as on a similar diet to 
which tyrosine was added in addition. Other experi- 
ments made with a diet of hydrolysed gelatin—which 
contains no tyrosine or tryptophane—showed that 
whilst the rats lost 18 per cent. in weight in a month, 
they lost little, if any, weight if tryptophane were 
added. The addition of tyrosine as well was without 
influence, and so it seems highly probable that the 
tissues of the mammal have the power of synthesising 
tyrosine. They form it from phenylalanine, but the 
small amount of this substance present in gelatin 
suggests the possibility that they can synthesise the 
benzene ring from non-aromatic substances. 
The second series of experiments relates to the 
synthesis of tryptophane in the body. It is known that 
some of the tryptophane of the food is excreted in the 
urine in the form of a quinoline derivative, kynurenic 
acid, and C. Asayama investigated the capacity of the 
tissues to carry out the reverse change. He found that 
rats fed on the amino-acids formed by the ‘prolon 
acid hydrolysis of caseinogen—a treatment which 
destroys all the tryptophane originally present—rapidly 
lost weight and died in eight weeks, though they grew 
moderately if tryptophane were added. If kynurenic 
acid were substituted for the tryptophane they lost 
weight and died at almost exactly the same rate as 
when no kynurenic acid was added at all, so we must 
conclude that whatever. the synthetic powers of the 
tissues for tryptophane may be, they do not extend to 
this substance. : 
EDUCATIONAL REFORM. 
HE Education Reform Council, which was founded 
last April at a conference called by the Teachers’ 
Guild, has issued a programme of education reform. 
The work of the council is as yet incomplete, and it 
is hoped to publish the full report early next year. 
Among other important recommendations enumerated 
in the programme the following deserve special men- 
tion. The Ministry of Education should hold a higher 
place in the hierarchy of the offices of the State, and 
the salary of the Minister should be equivalent to that 
of other principal Secretaries of State. Progressive 
organisation is hindered by certain statutory distine- 
tions between higher and elementary education, Local 
authorities for higher education should be obliged to 
supply or aid the supply of higher education, and the 
limit of 2d. to the higher education rate in the county 
areas should be removed. For the purpose of co- 
ordinating the activities of local education authorities 
with those of the universities and institutions for 
higher education, the country should be divided into 
educational provinces, the areas of which should be 
larger than those of the existing local authorities. 
The number of efficient secondary schools of varying 
types should be increased. The Consultative Com- 
mittee has advised the strengthening of the higher 
work of secondary schools, and the Reform Council 
considers that schools taking the lower grant should 
receive grants for this purpose. Pupils at any school 
