Marcu 21, 1912] 
air vacuum. The bacteria used comprised B. coli, 
B. typhosus, Staphylococcus pyogenes aureus, B. 
pyocyaneus. The action of light was excluded during 
the experiments. B. typhosus and B. coli, died both 
in vacuo and in air-dried slips within five days. 
S. pyogenes aureus persists considerably longer under 
both conditions. The interest centres around B. pyo- 
cyaneus. Air-dried films did not survive beyond nine 
days. 
months. B. pyocyaneus was submitted in vacuo to 
the action of heat, and also to the sun’s rays (the 
sealed vacuum tubes being submerged in water). Its 
resistance to these agencies, in the dried state, in 
vacuo, was not materially, if at all, increased. The 
bacillus was killed, moreover, by the action of ultra- 
violet rays on being removed from the vacuum and 
treated in an atmosphere of nitrogen. So far as the 
possibility of interplanetary bacterial life is concerned, 
it is evident that bacteria in the fully dried state, if 
free in the interplanetary vacuum, would be killed by 
the solar light. As Sir James Dewar’s experiments 
have demonstrated that the ultra-violet ravs will kill 
undried bacteria whilst in the frozen condition at the 
temperature of liquid air, there is little to support the 
hypothesis that the living protoplasm on the earth 
originally immigrated from interplanetary space in a 
free or unincluded condition—that free, particulate life 
has entered the earth’s atmosphere, as a result of light 
propulsion, from extramundane space. 
Zoological Society, February 20.—Dr. A. Smith 
Woodward, F.R.S., vice-president, in the chair.— 
Dr. A. T. Masterman: Recent investigations on age- 
determination in the scales of salmonoids, with special 
reference to Wye salmon.—Dr. H. Lyster Jameson : 
The structure of the shell and pearls of the Ceylon 
pearl-oyster (Margaritifera vulgaris, Schum.); with 
an examination of the cestode theory of pearl produc- 
tion. The author began by reviewing the work on 
the subject of pearl production carried out in Ceylon 
by Prof. Herdman, F.R.S., and his successors. He 
examined the theory, enunciated by Prof..Herdman, 
that most Ceylon ‘‘fine’’ pearls had for their nuclei 
the remains of cestode larvz, and that these larve, 
which are abundant in the liver and connective tissues 
of the pearl-oyster in Ceylon, were the “‘cause”’ of 
the most valuable pearls. Dr. Jameson maintained 
that the evidence adduced in support of this theory 
by Prof. Herdman and Mr. Hornell was insufficient. 
The second part of the paper dealt with the structure 
and formation of the shell and of pearls. The various 
repair-substances, which replace the ordinary shell 
substances under abnormal or pathological conditions, 
were described, their relations to the normal sub- 
stances of the shell were discussed, and their occur- 
rence in the pseudo-nuclei of pearls dealt with. The 
“‘calcospherules’? which Herdman regarded as free 
concretions, and as the cause of ‘‘muscle pearls,’ 
were considered to be in fact minute pearls, composed 
of the hypostracum, or special shell-substance to which 
the muscles are attached. The author maintained 
that, as he had already laid down in his 1902 paper, 
the real cause of pearl production would have to be 
sought, not in the nuclei or pseudo-nuclei of pearls, 
but rather in the pathological conditions under which 
the tissues of the mollusc gave rise to the pearl-sac.— 
R. Shelford: Mimicry amongst the Blattidze; with a 
revision of the genus Prosoplecta, Sauss. The author 
dealt with a number of exceptions to this usually 
cryptically coloured type of cockroach, and in greater 
detail with the Prosoplecta, nearly all the members 
of which presented a remarkably close and detailed 
resemblance to other insects.—Rev. O. Pickard- 
Cambridge: A contribution to the knowledge of the 
NO. 2212, VoL. 89] 
The slips kept in vacuo were alive at seven | 
NATURE 
77 
spiders and other arachnids of Switzerland. The 
paper was based on a number of specimens collected 
for the author by various persons, at different times, 
and contained the description of one new species. 
March 5.—Sir J. Rose Bradford, F.R.S., vice- 
| president, in the chair.—H. L. Hawkins: The classi- 
fication, morphology, and evolution of the Echinoidea 
Holectypoida.—H. G. Plimmer: The blood-parasites 
found in the Zoological Gardens during the four years 
tgo8-11. The paper contained the results of examina- 
tion of the blood of 6430 animals, in about 7 per cent. 
of which parasites were found. Many of these para- 
sites were described for the first time, and in other 
cases the hosts were newly recorded.—Prof. G. O. 
Sars: Zoological results of the third Tanganyika ex- 
pedition, conducted by Dr. W. A. Cunnington, 
1904-6. Report on some larval and young stages of 
| prawns from Lake Tanganyika.—Dr. R. Broom: The 
structure of the internal ear, and the relation of the 
basi-cranial nerves in Dicynodon, and on the homo- 
logy of the mammalian auditory ossicles. 
Royal Microscopical Society, February 21.—Mr. H. G. 
Plimmer, F.R.S., president, in the chair.—Mr. 
Rousselet : Fourth list of new Rotifera since 1889. The 
year 1889 was when Hudson and Gosse’s monograph 
of the Rotifera was completed by the issue of the sup- 
plement, recording altogether 400 species at that time. 
The author explained that his three preceding lists, 
published in 1893, 1897, and 1902, contained 393 new 
species, and the fourth list now submitted 214 names, 
a total of 607 new species since 1889. Mr. Rousselet 
estimated the present Rotiferous population of the 
world comprised 857 species. The greatest number of 
new species in the present list appeared amongst the 
Bdelloid Rotifers; tor species, mostly described by 
James Murray, were obtained from moss collected by 
him from all parts of the world, from Scotland to the 
Antarctic regions. Of the other orders represented 
there were Rhizota, 8; Ploima-Illoricata, 30; Ploima- 
Loricata, 74; and Scirtopoda, two new species. 
Linnean Society, March 7.—Dr. D. H. Scott, 
F.R.S., president, in the chair.—Prof. Percy Groom : 
Note on the internodes of Calamites. The author 
contended that the nodes corresponded to a cycle of 
growth during the vegetative season, and supported 
his views by measurements supplied by Dr. F. J. 
Lewis.—Rev. T. R. R. Stebbing: Historic doubts 
about Vaunthompsonia. The author pointed out that 
the number of the Natural History Review for July, 
1858, was received by the British Museum at the date 
stamped as “16 JY 58,” thereby proving its priority 
over Vaunthompsonia. 
Mathematical Society, March 14.—Mr. J. E. Camp- 
bell, vice-president, in the chair.—G. T. Bennett : The 
cubic surface as a degenerate quartic.—E. B. Elliott : 
Differential operators which generate all seminvari- 
ants and all ternary covariant sources.—W. H. 
Young: Goursat’s form of Cauchy’s theorem (in- 
formal). 
Mineralogical Society, March 12.—Prof. W. J. Lewis, 
F.R.S., president, in the chair.—Dr. G. F. Herbert 
Smith and F. N. A. Fleischmann; The zeolites from 
Killyflugh and White Head, Co. Antrim. Chabazite 
occurs in three different kinds of crystals and 
gmelinite in two, and the former is found pseudo- 
morphous after calcite. Analcite occurs in clear trap- 
ezohedra, and natrolite in fine needles. The character 
of the occurrences was described.—Dr. J. Drugman: 
Quartz twins. Further specimens of bipyramids, 
twinned on the primary rhombohedron, from the 
Esterel, France, were shown, thus establishing this 
mode of twinning, which was first described by Q. 
