352 
NATURE 

for the equinox 1900-0, and the proper motions are 
given for both amount and direction. Remarks 
regarding uncertainties in proper motions are added, 
and in the case of double stars, the number in Burn- 
ham’s General Catalogue is given. Attention is 
directed to a list by Innes of proper-motion stars 
south of —19°; this appeared subsequent to the print- 
ing of the present paper, and Mr. van Maanen adds 
the numbers of Innes’s list which should be included 
in his communication. 
Orpits OF VARIABLE RaprtaL VELOciITy Srars.—In 
the April number of the Journal of the Royal Astro- 
nomical Society of Canada some reductions are given 
of the measures of the variable radial velocities of 
stars. The orbit of 136 Tauri, deduced by J. B. 
Cannon, is based on sixty plates taken at the Ottawa 
Dominion Observatory between November, 1911, and 
January, 1915. The paper gives a list of the observa- 
tions. The spectrum of this star is of the A type, 
and the deduced period is 5-969 days. The same writer 
deals also with the orbit of € Andromedz, a star of 
the IX type spectrum, and utilises fifty-eight plates 
taken at the same observatory between September, 
1913, and February, 1915. On the average about 
twelve lines were measured on each plate, and, gener- 
ally speaking, the agreement was very fair. The final 
period derived was 17-767 days. In both of the above 
stars comparisons are made with the Lick Observa- 
tory results. The orbits of the spectroscopic com- 
ponents of 50 Draconis are discussed by W. E. Harper 
from the velocities of the ten plates secured at the 
Yerkes Observatory, and thirty-four taken at the 
Dominion Observatory. Both spectra were of the 
A type. The Yerkes and Ottawa observations both 
indicate a period of 4-120 days. The determination of 
the orbit of the spectroscopic binary, 1149 Groom- 
bridge, was also undertaken by the same writer using 
thirty spectrograms secured at Ottawa and three 
secured by Adams. The star is of the A5 type, and 
the spectrum has numerous lines well adapted for 
measurement. In the list of final elements derived the 
period is given as 9-944 days. 
MANCHESTER ASTRONOMICAL SOciETY.—No. 1 of the 
Journal of the Manchester Astronomical Society, for 
the session 1913-14, gives a brief account of the origin 
of the society and a statement as to its growth since 
its foundation in 1903. The object is for the asso- 
ciation of amateur astronomers, for mutual help, their 
organisation in the work of astronomical observation, 
and the encouragement of a popular interest in astro- 
nomy. The society numbers at present 131 members, 
and its president is the Rev. A. L. Cortie, S.J. The 
journal gives excellent portraits of the present and past 
four presidents ; and the address of the president on the 
origin of the sun and stars is printed and illustrated 
with three plates. A paper on Japanese and other 
magic mirrors is from the pen of the late Mr. T. 
Thorp, who was an original and active member of the 
society. Lunar photography, by Mr. William Port- 
house; astronomy and esthetics, by Mr. E. Denton 
Sherlock; and a remarkable solar prominence, by Mr. 
A. Buss, form the subjects of other papers printed 
in this issue. 

CONSTITUENTS OF EXTRACTS DERIVED 
FROM ALBUMINOUS SUBSTANCES. 
A. JOINT meeting of the Society of Public Analysts 
and the Biochemical Society, which was held at 
the Chemical Society’s Rooms on May 5, was devoted 
to the discussion of the methods adopted in estimating 
the nitrogenous constituents of extracts derived from 
albuminous substances, such as meat extracts. Mr. 
NO. 2379, VOL. 95] 


[June 3, 1915 


, A. Chaston Chapman, the chairman, in opening the 
discussion, pointed out that from the technical point of 
view the purposes to be served by such analyses were, 
first, to indicate the general character of the process 
by which any particular extract had been prepared; 
secondly, to throw some light on the source of the 
extract and its genuineness or otherwise; and, finally, 
to furnish information as to the physiological proper- 
ties of dietetic value. He then gave an outline of the 
existing methods of analysis, and emphasised their 
limitations; more particularly the practice of returning 
the ‘‘residual nitrogen’’ as “‘meat bases,” using the 
factor 3:12 for the conversion was a source of un- 
certainty and confusion, especially as Hehner had 
suggested the use of the ordinary protein factor, 6:25, 
for the same purpose. The best plan was to return 
the actual nitrogen percentages. 
Dr. F. Gowland Hopkins, dealing with the ques- 
tion of the food value of meat extracts and similar 
preparations, pointed out that the animal body dealt 
not with the intact proteins, or even with the albu- 
moses and peptones, but with the free amino-acids 
which were the individual constituents of the protein 
molecules. The way in which these acids were 
grouped in the protein molecule was not of much 
consequence, but the effects produced by the individual 
amino-acids were of extreme importance. He de- 
scribed physiological experiments which he had made 
showing that when rats were given a diet including a 
complete amino-acid mixture corresponding with the 
proteins of an ordinary diet, the growth was almost 
exactly normal, but when arginine and histidine were 
removed from the mixture, growth ceased imme- 
diately, but was again resumed when the missing 
constituents were added. The removal of tryptophane 
produced similar results, and Osborne and Mendel 
had, in America, shown that cystine was similarly 
essential. It did not follow that this was the case 
with every amino-acid, and the question as to which 
of these were vitally necessary offered a large field 
for investigation. Experiment had shown that in the 
case of rats, the critical minimum for arginine lay 
somewhere between 24 and 1 per cent. The functions 
of the individual amino-acids were not confined merely 
to flesh formation. Thus, for example, the effect of 
feeding animals on zein, which was deficient in both 
tryptophane and lysine, was not only to restrict growth, 
but to shorten the survival; the same was true with 
zein plus lysine, but with zein plus tryptophane the 
animal was able to maintain its weight for a long 
period, although it did not grow. 
Dr. E. P. Cathcart said that observations at present 
available were so scanty that it could not be said 
with certainty that creatine and creatinine had a 
special niche in the organism. He did not think that 
any end would be gained by the separate estimation 
of these two substances. Mr. A. R. Tankard and 
Mr. E. Hinks dealt with questions of procedure, and 
Dr. Percival Hartley described his experience of Van 
Slvke’s method of estimating amino-nitrogen; further 
remarks were made by Dr. Rideal, Prof. Barger, Dr. 
Harden, and Dr. S. Walpole. 
MUSEUMS AND EDUCATION. 
HE Museums Journal for May contains an in- 
teresting and suggestive article on the educa- 
tional work of American museums, by the director of 
the Charleston Museum. It is abundantly clear from 
this that the functions of the museum in America are, 
so to speak, intensively cultivated. And nowhere. is 
this more apparent than in the facts which he gives 
in regard to the co-operation which has grown up 
between the museums and the public schools. It is 
! now the rule, he tells us, for children to be brought 
