December 21, 191 1] 



NATURE 



243 



it, so far as it goes, is well selected and in the main 

 correct. 



Many a " creeper " and new hand on Eastern estates 

 and elsewhere will owe Mr. Frank Braham a debt 

 of gratitude for this hand}' little volume, which doubt- 

 less is the nucleus of a future work of more extended 

 scope, not one with large type on art paper, but a 

 planter's " Molesworth," of use to the old hand as 

 well as to the beginner. 



The author's section on general information will be 

 found specially useful, and his essential rules for the 

 preservation of health in tropical climates are 

 admirable if intended for the young planter going out 

 to the East for the first time ; but for the older resident 

 in the tropics "drink as little as possible — fluids in- 

 flate the bowel " is dangerous advice. The ingestion 

 of a suflicient quantity of water or other bland liquid 

 is essential if for no other reason than to counter- 

 balance the effects of excessive perspiration. In hot 

 w eather the kidneys are very largely relieved of their 

 <-xcretory duties by the skin. If then the individual 

 for years has been in the habit of still further relieving 

 them by drinking as little as possible, it is not 

 astonishing that in cases of emergency they are unable 

 to return to their normal state of efficiency, and if 

 ' lackwater fever is encountered death in such cases 



ay be the result. 



In these essential rules also mention of the all- 

 important hot bath and change at sundown would have 

 added to their completeness. The book, however, 

 should comqiand a ready sale. 



Die tnoderne graphische Reprodiiktiotu Ein Fiihrer 

 und Ratgeber durch das Gebiet des Jllustraiions- 

 ivesens unter Berucksichtigung der filr die Wicder- 

 gabe bestimmten Originate. Gemeinverstiindlich 

 dargestellt von L. P. Mosler. Pp. vi + 52 + xiv 

 plates. (Jena: Gustav Fischer, 1911.) Price 2 

 marks. 



In this booklet the author gives a concise description 

 of the methods of illustration as at present practised, 

 so that those who desire to avail themselves of such 

 methods may have some idea of their characteristics 

 and possibilities, and be guided as to their choice. 

 He refers also, shortly, to methods of making draw- 

 ings and photographs for reproduction. Following 

 the text are fourteen plates. Nine of these are im- 

 pressions from half-tone blocks made from the same 

 original to show the effect of the fineness of the 

 screen, a reproduction of a reproduction, a "duplex" 

 print, &c. There are also a four-colour print, a 

 •collotype, and a photogravure. 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



The Distastefulness of Anosia pUxippm:. 

 Refkrring to tlip iiitorostiiif^ note on '* The Distasteful- 

 Tioss of Anosia plc.xippus " in Naturk of October 12, I 

 should like to sujijjijpst that the experiment, though interest- 

 ing in itself, does not materially strengthen the case for 

 the usefulness of mimicry. To make a good rase for 

 mimicry in the sense in which that term is ordinarily 

 used, the mimic Basilarchia archippus should be tested and 

 found palatable. Further, if mimicry means anything at 

 II with reference to these two species, North American 

 rds should eat some butterflies but not molest Basilarchia 

 rhippus. So far as observations have been reported, 

 \inorican birds eat butterflies very rarely, and there is no 

 iflonce, so far as I know, either from direct observa- 



NO. 2199, VOL. 881 



tion or from the thousands of stomach-content examina- 

 tions made by the United States Department of Agri- 

 culture, that its non-mimetic relatives are eaten more 

 often than Basilarchia archippus. 



If European birds show the same indifference towards 

 butterflies as is manifested by North American birds, either 

 the " model," Anosia plexippus, or the mimic, Basilarchia 

 archippus, might with impunity become widely dis- 

 seminated in Europe. • A. M. Bant.a. 

 . Cold Spring Harbor, N.Y., November 20. 



I HAVE a shrewd suspicion that if the result of my 

 experiments upon Anosia plexippus had proved this butter- 

 fly to be highly palatable, the dwindling minority of 

 mimicry sceptics would have made the very most of the 

 fact, and claimed that it " materially strengthened the 

 case" against Bates's theory of mimetic resemblances; 

 and in this they would have been perfectly right, so far, 

 at all events, as the particular instance is concerned. 

 But since the experiments proved the precise opposite, 

 those who believe in the theory may reasonably maintain 

 that the case" for the usefulness of the mimicry to Basil- 

 archia archippus is thereby materially strengthened. It 

 appears to me that few more important items of evidence 

 in favour of the theory of mimicry can be established than 

 demonstration of the distastefulness of " models." 



Again, I think Mr. Banta overrates the negative evidence 

 he cites in support of the view that birds seldom prey upon 

 butterflies under natural conditions. My opinion to the 

 contrary is based upon a large number of experiments 

 made in the gardens of the Zoological Society of London, 

 and published in the Proceedings of the society for 

 September. I can recollect no exception to the rule that 

 insectivorous birds were roused to attention at once by the 

 sight of butterflies, their keenness suggesting very forcibly 

 that they knew them, either by instinct or by experience, to 

 be part of their natural diet. 



Not less strongly suggestive was the determination with 

 which they pursued, and the precision with which they 

 generally caught, the butterflies on the wing when let loose 

 in the shelterless aviary. Conversely, the skill evinced by 

 the butterflies in dodging their pursuers in mid air was 

 one of the most striking features of the experiments. Just 

 as one is compelled to believe that the instinctive doubling 

 of the coursed hare when overtaken by greyhounds in- 

 dicates the habitual method of escape of the species from 

 fleet-footed foes, so must one believe that the evasive twist 

 of a butterfly when pursued by a bird is an inherited habit 

 that has proved a means of salvation to members of that 

 species in the past when chased by similar enemies. If, 

 as is maintained, birds do not under natural conditions 

 prey upon butterflies to a sufficient extent to be reckoned 

 as serious enemies, what explanation is to be offered of the 

 marked reaction observable between the two sets of animals 

 when pitted against one another? R. I. PococK. 



Zoological Society, December 6. 



The Weather of 1911. 

 I HAVE studied with great care and interest Dr. Shaw's 

 letter in Nature of November 30 disclosing a promising 

 field of inquiry into the causes of such abnormalities of 

 weather as we have, for example, experienced during the 

 summer and first half of the autumn of the present year. 

 Seizing hold of the very fact Dr. Shaw's letter refers to, 

 which has apparently induced him to look in the direction 

 of the upper atmosphere above 9 kilometres for new lines 

 of investigation, namely, that certain types of distribution 

 of barometric pressure, normally rainy, occasioned little 

 or no rainfall in the summer of ion, I had before reading 

 his letter entertained the idea that somehow or other the 

 persistent, parching drought might have been due to an 

 abnormally reduced absolute humidity of the atmosphere 

 (at least of those strata not immediately in contact with 

 surface water supplies) over these islands, so much reduced 

 that the convection currents adequate to produce rain in 

 I more normal conditions failed to do so in the present year. 

 I admit, of course, that a decreased absolute humidity of 

 the air in hot summer weather, with the ocean all round 

 us, would be a very different thing to account for. and 

 perhaps could only be brought about by a per';i>;tont flow 



