i6 



NATURE 



[November 3, 1892 



to be quite trustworthy. From the size and richness of the 

 convolutions, the sufficiency of the grey matter both on the 

 surface and in the interior of the hemispheres, and from the 

 remarkable number of the white fibres, especially of the trans- 

 verse commissural ones, the brain of Mr. Grote is pronounced 

 to have been of very perfect and high organization. 



The method of cleaning mercury adopted at the Physikalisch- 

 technische Reichsanstalt at Berlin is described in the Zeitschrift 

 fur Jnstrutnentenkunde. The raw material is brought in iron 

 bottles from Idria. It is filtered'and dried, and twice distilled in a 

 vacuum to get rid of the heavy metals. Great care is taken to 

 eliminate fatty vapours derived from greased valves and cocks, 

 which is accomplished by means of a mercury pump working 

 without a stopcock. Finally, the electro-positive metals, such 

 as zinc and the alkalies, are separated by electrolysis. The 

 mercury is precipitated from a solution of mercurous nitrate ob- 

 tained by the action of nitric acid on excess of mercury. The 

 solution, together with the impure mercury acting as an anode, 

 is contained in an outside glass vessel, into which a current from 

 a GUlcher thermopile is conducted by an insulated platinum 

 rod. The cathode rod dips into an interior shallow glass vessel, 

 in which the pure mercury is collected. On careful analysis it 

 was found that no perceptible non-volatile residue was left by 

 200 grammes of the purified metal. Thus the mercury is well 

 fit for use in standard barometers and resistances. 



With regard to the revival of animals after exposure to great 

 cold, Herr Kochs (in the Biologisches Centralblatt) points out 

 two things which retard formation of ice in the animal body. 

 First, the body does not contain pure water, but salt and albumen 

 solutions, which only freeze under zero C. Then capillarity and 

 adhesion hinder freezing. Herr Kochs states that water in a 

 glass tube of o'3 to 0*4 mm. diameter maybe cooled to - 7° and 

 even — 10° C. without freezing. With a diameter of only o*i to 

 o'2 mm. the water is not frozen, even though the end of the 

 tube be put in freezing liquid. Thin liquid sheets between two 

 glass plates behave in the same way. If a salt solution freezes, 

 the salts are excluded ; and pure water, in freezing, gets rid of 

 its absorbed gas. Fresh blood, according to the author's ex- 

 periments, freezes only after being strongly cooled to — I5°C., 

 and after complete elimination of gases and salt3. The blood 

 corpuscles are dissolved and the blood lo?es colour. The same 

 elimination doubtless occurs in freezing of protoplasm. Ex- 

 periments cited to show the possibility of "anabiosis" may 

 probably be explained by the decomposition process not having 

 gone so far as to bring life completely to a standstill. Similar 

 results were obtained in experiments on drying of seeds and 

 various animals. It was shown with what tenacity many 

 animals, under most unfavourable circumstances, retain the 

 moisture necessary to life. 



The very destructive American disease of the vine known as 

 the " Black-rot" has, for some years past, made its appearance 

 in Europe, and its life-history has now been thoroughly investi- 

 gated by Viala, Rathay, and others. The ravages of the disease 

 have been traced to a parasitic fungus, Lcestadia Bidwellii, the 

 mycele of which develops in the interior of the organ attacked, 

 chiefly the young branches and berries, and produces sper- 

 mogones and pycnids in the course of the summer. It is especially 

 by the pycnospores that the fungus is disseminated. Towards the 

 end of the period of vegetation sclerotes are formed, usually within 

 the pycnids, and the conidiophores spring from these. Peritheces 

 are also formed in May and June on the fallen and infected 

 berries of the previous year. Until recently the ravages of this 

 pest in Europe were confined to the French vineyards, but it has 

 recently been^detected in Austria and in Italy. The most effectual 

 remedy for it is salts of copper. 



NO. 1 201, VOL. 47] 



The results obtained from the botanical work done at the 

 various experiment stations in the United States will in future be 

 published in the form of an " Experiment Station Record," issued 

 by the Department of Agriculture, under the editorship of Mr. 

 Walter H. Evans. 



Anglo-Indian papers record the presentation of an interest- 

 ing " piece of architecture " to the Madras Central Museum by 

 Lord Wenlock. It is a hornets' nest, belonging probably to the 

 species Vespa cincta. It is conical in shape, and is constructed 

 of a material resembling rough paper or cardboard composed of 

 woody portions of plants gummed up by the insects, and brought 

 into the condition of paste by means of a viscid salivary secretion. 

 The combs are placed in tiers and attached to each other by 

 small columns of the same paper-like material of which the nest 

 is composed. It is two feet in height, and about the same in 

 circumference at the base. It was obtained in the course of one 

 of His Excellency's tours. 



M. DE Nadaillac, in the current number of La Nature, 

 discusses the significance of some of the facts which have 

 been brought to light by the recent excavations of mounds in 

 the Ohio Valley. The mound builders knew how to construct 

 earth fortifications, which were of considerable extent and always 

 remarkably adapted to the sites chosen. They buried their 

 dead under tumuli of astonishing dimensions. Copper was the 

 only metal they could work, and they undertook long journeys 

 in search of it. Their weapons and implements were of stone. 

 They made vases of pottery, and were able to produce repre- 

 sentations of the human figure and of animals, both by sculp- 

 turing them in stone and by modelling them in clay. At least 

 in some districts they were sedentary, and, like all sedentary 

 populations, they had to obtain the means of subsistence in part 

 by cultivation of the soil. They were often engaged in fighting, 

 and numerous burials in which the bodies are crowded together 

 bear witness to the fury of their struggles. Whence did they 

 come and who are their descendants ? M. de Nadaillac thinks 

 that these questions can never be definitely answered unless 

 investigators discover some traces of the language of the mound - 

 builders. 



An interesting and valuable paper on the association of 

 shipping disasters with colour-blind and defective far-sighted 

 sailors, read by Dr. T. H. Bickerton before the section of 

 Ophthalmology at the last annual meeting of the British Medical 

 Association, has been reprinted for the author from the British 

 Medical Journal. Dr. Bickerton takes anything but a hopeful 

 view of the prospects of legislation on this important question. 

 He greatly fears that "many a shipping disaster will occur 

 before the Royal Society's suggestions become part of the law of 

 the land." Accordingly he urges all who interest themselves in 

 the subject to abate not a tittle of their endeavours. "There 

 are none," he says, " so difficult to convince as those who will 

 not believe, and the men who have had the framing of the rules 

 of the road at sea are the very men who hitherto have turned 

 from all suggestions on the eyesight question with contempt. 

 True it is that their language, judged from examples to be found 

 in the Nautical Magazine, is becoming moderate, and even 

 polite, but they lack knowledge of this subject, and they will 

 still require our best attention." Meanwhile, Dr. Bickerton 

 presses on the attention of the public the following facts : — that 

 4 per cent, of the whole male population are colour blind ; that 

 about 8 per cent, more have marked impairment of sight from 

 refractive errors ; that there is no official test whatever as to a 

 sailor's eyesight; that a man may be the subject of any of the forms 

 of eye disease, may have any degree of blindness, or may be so 

 short-sighted as to be unable to see distinctly more than a few 

 inches in front of his nose, and yet be at perfect liberty to be a 

 sailor and to become an officer ; and that, although there is a 



