December 12, 1895] 



NATURE 



135 



that such actinic rays increase an inflammation already existing, 

 as is the case in smallpox. The latest contribution to the 

 l<nowledge of this action appears in the British Medical 

 Journal, in which Dr. N. R. Finsen, of Copenhagen, gives the 

 results obtained by keeping small-pox patients in non-actinic 

 light. The following are the main points concerning the treat- 

 ment : — (i) The excUision of the chemical rays must be abso- 

 lute ; even a brief exposure to daylight may produce suppuration 

 and its sequela*. In other words, the skin during small-pox is as 

 susceptible to daylight as a photographic plate, and must be 

 kept from the chemical rays in the same way and almost as care- 

 fully. If, therefore, red window glass is employed, it is neces- 

 sar}- for it to be of a deep red colour, and if curtains are used, 

 they must be very thick or in several layers. When the patient 

 takes his meals, or during the physician's rounds, artificial light 

 — for instance, faint candle-light — may be used without any 

 danger. (2) This method does not prevent but allows the em- 

 ployment of any other treatment which may be considered 

 necessary. (3) The treatment should be commenced as early as 

 possible ; the nearer the commencement of the suppuration the 

 smaller the chance of success. (4) The patient must remain in 

 the red light until the vesicles have dried up. 



One ofthe difficulties which attends the production of the new 

 serum remedy for diphtheria is the uncertainty which accom- 

 panies the elaboration of toxic products by the diphtheria bacilli 

 in culture media. This diphtheria-toxine, as it is called, has to be 

 produced on a large scale, and it must be of a requisite degree of 

 virulence, or it will not,whensubsequently inoculated into horses, 

 endow the blood-serum of the latter with the necessary degree of 

 diphtheria-immunising properties. Even the bacilli taken direct 

 from the throat of a diphtheria patient are not capable of elabor- 

 ating, in culture media, toxines of a sufficient strength for the 

 purposes of anti-dijJitheritic serum production, and recourse has 

 to be had to increasing their virulence by first inoculating them 

 into guinea-pigs, and then transferring them to the culture media. 

 The reason of this most inconvenient idiosyncrasy, so character- 

 istic of diphtheria bacilli, has until recently not been surmised, 

 but Prof. Spronck of Utrecht has unravelled the mystery in a 

 most interesting manner. 



The last number of the" Archives des Sciences Biologiques, 

 published by the Imperial Institute of Preventive Medicine in 

 St. Petersburg, gives the annual report on the anti-rabic 

 inoculations carried out during the past year in St. Petersburg 

 and Odessa respectively. In St. Petersburg, 224 persons were 

 treated by Pasteur's method, and only three succumbed to 

 hydrophobia. In two of these cases death ensued during the 

 treatment and before, therefore, the inoculations had produced 

 their full effect ; in the other case, the patient was not treated 

 until thirteen days after he had been bitten, and he died just 

 three weeks after the inoculations had been completed. 

 Amongst the rabid animals, 193 were dogs, 18 wolves, 7 cats, 

 5 horses, and i pig. At Odessa, no less than 984 persons were 

 inoculated anti-rabically, the larger number of persons so treated 

 being between twenty-one and forty years of age. The death- 

 rate from hydrophobia, including those persons who died before 

 the treatment was completed, was equal to 0*32 per cent. An 

 instance is recorded of a death from hydrophobia having taken 

 place one year after the anti-rabic inoculations were completed- 

 The patient was severely bitten on his hands by a mad dog, and 

 presented himself a week later at the Institute, although the 

 wounds had been cauterised three hours after their infliction ; the 

 inoculations were completed on July 14, 1893, and on July 15^ 

 1894, he died of hydrophobia. At Odessa the largest number 

 of cases were admitted in the months of May, June, and July ; 

 but at St. Petersburg, contrary to the usual experience, the maxi- 

 mum number of patients were received in the spring and 

 autumn respectively. 



NO. 1363, VOL. 53] 



A NUMBER of interesting observations of the habits of the 

 common bat and the long-eared bats in captivity are recorded by 

 Mr. John D. Batten in Nature Notes for December. Common 

 bats appear to be practically blind, yet Mr. Batten mentions that 

 he never knew a bat fly against a window or against any obstacle : 

 light or darkness apparently making no differences in its flight. 

 Long-eared bats appear to see better than common bats, and their 

 hearing is much more acute. There is seldom any difficulty in 

 inducing bats to feed. Mr. Batten fed his bats at first on flies, 

 moths and grasshoppers, but when these became scarce, he fed 

 them almost entirely upon meal-worms. It is remarkable that 

 bats, on being captured, readily adopt an entirely new method of 

 life, and the new habits thus acquired quickly become natural. 

 When bats are asleep in October and November, they take 

 sometimes as long as a quarter of an hour to awaken. Mr. 

 Batten has observed the process carefully, and finds it to be 

 always the same. He thus describes it: "The bat when 

 thoroughly asleep is cold, dead cold to the touch. If I then 

 took it in my hand it would not attempt to move about or seek 

 for food, but lie quite still. On putting it to my ear I could 

 hear a throbbing begin, at first very slowly and not very 

 regularly, more than a second between the beats. Gradually 

 the throbbing became quicker and quicker until it was 

 impossible to count the beats, at the same time the 

 warmth of the body was increasing very rapidly, and the bat 

 quivering visibly. At last the throbbing becomes a continuous 

 whirr, not unlike the purring of a cat, and the body feels quite 

 hot to the hand. Then, rather suddenly, the throbbing quiets 

 down like water coming to the boil, it slows somewhat, and 

 becomes almost inaudible. The bat coughs or sneezes, chatters 

 a little with its teeth, and begins to move about expecting to be 

 fed." Of three bats set to hibernate at the end of November 

 in 1890, two were found dead at the end of the following 

 January, and one was alive and perfectly strong ; its fur was in 

 good condition, and it fed well, and the hibernation had not 

 affected its power of flight. 



The occurrence of perlitic cracks in a rock of stony texture 

 has always been held as evidence of its alteration from . an 

 originally glassy state ; but within the last two years doubt has 

 been cast on this conclusion through Mr. W. W. Watts's observ- 

 ations on the pitchstone of Sandy Braes, in which perlitic cracks 

 were claimed as traversing the quartz and other crystals as well 

 as the matrix. In a paper read before the Royal Society of New 

 South Wales, Mr. W. F. Smeeth has, in connection with a 

 description of a local pitchstone resembling that of Sandy Braes, 

 discussed fully the exact mode of origin of perlitic cracks and 

 the features which distinguished them from other curved cracks. 

 He points out that the artificial perlitic structure that can be 

 made in a Canada balsam film is a " two-dimensional phase of 

 the natural structure," and from its characters he tries to deduce 

 those of the tri-dimensional phase. His conclusion is that 

 natural perlites are " cracks of more or less irregularly spiralloid 

 character, occurring in the interspaces between sets of polygonal 

 cracks." Allowing for irregularities due to want of homogeneity 

 in the lava, and for the fact that, whereas in the artificial struc- 

 ture the axes of the spirals are all normal to the surface of the 

 film, the axes of the natural spiralloids are variable in direction, 

 he deduces a series of possible figures for sections of true (tri- 

 dimensional) perlitic structure. The most obvious of the 

 characteristics shown by these theoretical sections is that the 

 curves never meet otherwise than tangentially. That these 

 theoretical figures are actually those seen in sections of typical 

 perlitic rocks, affords strong evidence of the correctness of the 

 views suggested as to their mode of formation. Passing on 

 to consider the curved cracks in the quartz crystals (shown by 

 the New South Wales specimen as well as by that described by 

 Mr. Walts), he points out that the cracks, instead of meeting one 



