November 19, 1891] 



NATURE 



53 



ment would correspond to a finished picture. With such 

 a conception I should prefer in Thesis IV. the metaphor 

 of a kaleidoscope. The pattern at any one point will determine 

 the pattern that succeeds, although, with an infinite number of 

 pieces, the latter must always be different. But though differing, 

 the successive patterns will resemble each other far more closely 

 than those which are separated by wide intervals. Similarly, I 

 do not think it is inconceivable that the arrangement of the 

 ancestral units may have a determining effect on the arrange- 

 ments which will succeed, in spite of the loss and restoration of 

 half the units in each generation. Such a conception has the 

 further advantage that it renders intelligible the action of ex- 

 ternal conditions on the germ-cells, either directly or through 

 the medium of the body-cells. The ancestral units may be 

 excessively stable, but the arrangements may be modified by a 

 shock, just as the pattern in a kaleidoscope may be changed by 

 a blow instead of the "normal " process of rotation (correspond- 

 ing, of course, to the loss and restoration of half the units). 

 Oxford, November i6. Edward B, Poulton. 



Town Fogs and their Effects. 

 The influence of fogs on health, referred to in the very 

 interesting paper by Dr. Russell (Nature, November 5, p. 10), 

 seems to call for further investigation. On the face of it, and 

 judging by the composition of fogs, the discomfort they bring, 

 their hurtfulness to plants, &c., fogs must surely damage health. 

 And the injurious effect, I would point out, might not be at once 

 apparent in the death-rate. What, on the other hand, is the 

 precise nature of the beneficial effect of fogs (for such there 

 seems to be) ? If they plague mankind, they probably also 

 plague those enemies of mankind, the minute organisms on 

 which disease depends. And if so, we might even suppose 

 some lives to be saved when fog comes on. It would be in- 

 teresting to hear from hospitals for special diseases, how the 

 patients are affected by fog. I understand that people suffer- 

 ing from asthma often rather enjoy a fog, or the sulphureous 

 atmosphere of the Underground Railway. Has this ever been 

 explained ? M. 



The Eclipse of the Moon. 



I VENTURE to send some notes upon last night's eclipse of 

 the moon, taken by me here up to 11.35 p.m., when the sky 

 became rather suddenly and entirely overcast. 



The first indication of the penumbra of the earth's shadow 

 was distinctly visible upon the north-east limb of the moon a 

 little before 10.25 '■> ^"^ ^^ 10.35 (time given by the almanac) 

 her north- east limb was well in shadow, and hidden by a re- 

 markably dense or black shadow. At this time the sky here 

 was quite clear, and promised to keep so for some time. At 

 10.45 the shaded part of the moon was so dark as to be invisible 

 upon the sky even through glasses. At 10.50 a very beautifully 

 coloured prismatic "cock's eye" formed in the sky exactly 

 opposite the shaded limb, taking a fan-like shape radiating from 

 that side of the moon ; the prismatic colours being repeated 

 twice, as in a double quadrant of a rainbow ; while the sky 

 round the bright part of the moon was clear and uncoloured. 

 At 10.55 a thin white cloud, with ring of prismatic colours, 

 formed round the moon ; the earth's shadow still remaining 

 very dark, with well-defined edge, and little or no penumbra 

 beyond it. At I1.5 the thin cloud entirely cleared, the shadow 

 still very dark, the upper and lower edges of the moon's limb 

 just visible as threads of light upon the sky ; and at II. 10 a very 

 slight warmish tint appeared about the north-east part of shadow. 

 At 1 1. 15 the sky very clear and dark about the moon, stars 

 before invisible coming out brightly. The earth's shadow was 

 now well advanced over the moon, strongly defined, and as dark 

 as the fky beyond it. At 11.22 light thin clouds again gathered 

 round the moon, a narrow crescent of her only remaining. At 

 11.25 the moon became wholly hidden by a dense cloud. At 

 about 11.35 I caught a momentary glimpse of the moon through 

 the cloud, a very small part of her south-west limb just showing. 

 At 11.40 sky entirely overcast; a faint aurora or red colour 

 spreading upward, apparently below this cloud or mist, from the 

 north. 



I have only to add that the darkness and absence of colour of 

 the shaded part of the moon was even more marked in this 

 eclipse — so long as I was able to observe it — than in that of 

 October 4, 1884, which was then set down to an abnormal 



NO. 1151, VOL. 45] 



density of the earth's atmosphere, and was supposed to have 

 some connection with the strange sunsets and other phenomena 

 of that period. I was not altogether unprepared for the same 

 general character in last night's eclipse, as, so far as my own ob- 

 servations go, I am led by them to believe that the conditions 

 then present in our atmosphere are still with us. 



Southampton, November 16. Robert C. Leslie. 



Comparative Palatability. 



The following observations were made during the last week 

 of September and first of October :— 



Two tadpoles of the small newt were taken by a "silver-fish." 

 Three others, placed next day in the globe containing this fish 

 and two goldfish, were not swallowed, though attempted from 

 time to time. A brandling {Allolobophora fcetidd) was once 

 taken by the same silver-fish ; but refused the next day and 

 afterwards. 



A large frog (?) ate brandlings readily. Two slugs were 

 taken by frogs. Tadpoles of the small newt were disregarded. 



A very interesting experiment was made with a brimstone 

 butterfly {Rhodocera rhamni i ). It was offered to a frog 

 vyhich had just taken a V. urtica. Though fairly seized several 

 times, the brimstone was always rejected. After one rejection, 

 a second V. urticce was swallowed ; after another, a Spilosoma 

 larva. The butterfly was then given to a spider, which attacked 

 it, but left it unwound. A V. urlicce placed in the web was at 

 once seized, partially wound, and sucked. Then the spider re- 

 turned to the brimstone ; but immediately left it again for the 

 Vanessa, which was thoroughly wound, sucked, and moved higher 

 up into the web. At dui>k, the brimstone had been very imperfectly 

 fastened. Next morning, however, it had been taken up by 

 the spider. 



That a frog is not much hurt by the nippers of Ocypus is 

 shown by the following experiment. A specimen which had 

 been taken from the side seized the frog's tongue, was rejected 

 after a few minutes, and removed by the forceps. The frog 

 immediately after took a large earthworm. 



Small frogs are exceedingly bold and voracious ; often attack- 

 ing prey which is as large as themselves, and which they could 

 not possibly swallow. House- and harvest-spiders, hairy and 

 smooth larvae (among them those of Spilosoma sp. and Matnestra 

 persicarict), ladybirds, earthworms, brandlings, and silver-Y 

 moths, were all swallowed somehow ; while large " devil's coach- 

 horses " were invariably attacked. Tadpoles of the small newt 

 were disregarded. E. B. TiTCHENER. 



Inselstrasse 13, Leipzig. 



The Inheritance of Acquired Characters. 



Will you allow me to call the attention of your readers to a 

 sentence in Mr. Hemsley's review of Schimper's and Karsten's 

 works on the mangrove vegetation ? " Mangroves grown in soil 

 free, or practically free, from chloride of sodium, develop foliage 

 of less substance, furnished with a larger number of stomata." 

 If this means, as I understand it, that the change takes place 

 immediately with the change in the conditions of growth, 

 it would be very interesting to have further details ; as the fact 

 would furnish a very strong argument that the peculiarities in 

 the mangrove vegetation are the result of the inheritance of 

 acquired characters. Alfred W. Bennett. 



St. Thomas's Hospital, November 7. 



"The Darwinian Society." 



In your issue of November 5 (p. 19) information is given 

 that a local Society is about to be inaugurated in Edinburgh, 

 under the title " The Darwinian Society." 



As the Society is apparently to be merely for the encourage- 

 ment of the study of natural science in the University of Edin- 

 burgh, the name is surely too pretentious to be suitable ; and it 

 is one that might well, I think, be kept in reserve for bestowal 

 in later years upon a chartered Society of similar magnitude 

 and as far-reaching extent as that founded in honour of Linnaeus. 

 It is therefore to be hoped that a more applicable name than 

 the one proposed may be found for the new Edinburgh 

 University Society. William White. 



Sheffield, November 10. 



