596 



NA TURE 



[September 16, 1922 



Research Items. 



Laughter. — In the Fortnightly Review for August 

 J. A. T. Lloyd considers the problem of humour and 

 mechanism. Bergson in his well-known study, " Le 

 Rire," maintains the hypothesis that the essence of 

 humour lies in the mechanisation of what ought to 

 be spontaneous and not mechanical. The function 

 of laughter is to punish and so to prevent the repetition 

 of machine-like behaviour. The author of this paper 

 criticises this point of view as being more true of 

 Latin humour than of Anglo-Saxon and supports 

 the theory that in the case of the latter, laughter is 

 rather due to a feeling of superiority. He thinks, 

 however, that recently a change has taken place, 

 and that in Mr. Stephen Leacock's humour we 

 approximate to humour as sensed by Bergson ; he 

 detects automata masquerading as human beings 

 and we laugh, but not with the old laughter of 

 superiority. A more fundamental treatment of the 

 subject of laughter will be found in Psyche (vol. ii. 

 No. 4), where Prof. McDougall develops at greater 

 length a theory he put forward in Nature some 

 years ago. He believes that the theories usually 

 advanced fail to answer the question, For what end 

 did the human species acquire the capacitv for 

 laughter ? Man is endowed naturally with the 

 tendencv to share the emotions of others, when he 

 sees them expressed by them in action, thus render- 

 ing himself extremely susceptible to the suffering 

 around him. Were he to suffer sympathetic- 

 ally every pain he saw, he would very rapidly 

 devitalise himself ; hence he has developed a com- 

 pensatory mechanism whereby he laughs at the 

 pains and sufferings which are not serious or with 

 which he can have no concern. Laughter is then 

 primarily and fundamentally the antidote to sym- 

 pathetic pain. It is necessary to distinguish laughter 

 from the smile which is the natural expression of 

 pleasure. 



Radula of the Helicinid^j. — This, judging from 

 the somewhat jejune remarks concerning the method 

 of preparation and mounting and seeming want of 

 acquaintance with the work of earlier writers on 

 the subject, appears to be the author's first encounter 

 with the molluscan radula. In these circumstances, 

 Mr. H. B. Baker (Proc. Acad. Nat. Sci. Philad. vol. 

 Ixxiv.) must be held to have acquitted himself well 

 and has rendered a useful and well-illustrated account 

 of the radula? of the Helicinidae that will prove useful 

 to future students of the group. Although the title 

 gives no hint of the fact, the author attempts a 

 classification of the North American Helicinidae 

 largely based on the characters of the operculum, 

 and further essays a phylogenetic scheme. 



The Structure and Biology of the Hog Louse. 

 — Memoir 51 of the Cornell University Agricultural 

 Experiment Station, by Miss L. Florence, is devoted 

 to a study of this insect and forms a carefully executed 

 piece of morphological work. With the exception of 

 the human louse, very few detailed studies have been 

 made of any species of Anopleura, and the present 

 papei fills a very noticeable hiatus. The complete 

 life-i \i k- from egg to egg at a temperature of 35° C, 

 followed out in vials worn next the body, was ascer- 

 tained to require 29 to 33 days. Of this period 

 13-15 days was occupied by the incubation of the 

 eggs and three ecdyses were passed through during 

 post-embryonic life. The difficult subject of the 

 mouth-parts is very fully discussed, but their homo- 

 logies are not touched upon more particularly owing 

 to the necessity for developmental studies made upon 



NO. 2759, VOL. I IO] 



the embryo. The only investigator who has dealt, 

 so far, with this aspect of the subject is Cholodkovsky, 

 in his work on Pediculus. Miss Florence finds that 

 the pharynx and mouth-parts of the hog louse are 

 similar in plan to those of the last-mentioned insect. 

 The result of the work, as a whole, is to emphasise 

 the general morphological similarity of the Mallo- 

 phaga and Anopleura, thereby supporting the con- 

 clusions of Mjoberg and of Harrison. 



Researches ox Diptera. — In Bulletin No. 5 (n.s.) 

 of the Canadian Department of Agriculture, Dr. A. E. 

 Cameron contributes a well-illustrated paper on the 

 structure and biology of Simulium simile, a small 

 black flv infesting cattle in Saskatchewan. This 

 insect, however, has not been observed to suck the 

 blood of man, although it may cause mild annoyance 

 to human beings by flying persistently around their 

 heads. The aquatic larva? and pupa? of this species 

 are extensively preyed upon by a fish known as the 

 sucker (Catastomus commersonii), which is proving 

 itself one of the most successful controlling agents. 

 As the result of experimental tests with miscible 

 (phinotas) oil it is shown that the Simulium larvae 

 can be killed. The experiments, however, did not 

 prove to be quite so satisfactory with the larvae of 

 S. simile in the river as with those of other species 

 in a small stream. In Bulletin of Entomological 

 Research, vol. 12, Part 4, Major W. S. Patton con- 

 tributes revisionarv notes on the genus Musca : in 

 this first part of the paper he deals with Oriental and 

 Australasian species. The role which these insects 

 plav in the dissemination of disease renders the exact 

 determination of very closely allied species a matter 

 of practical importance. Mr. F. W. Edwards (Ento- 

 mologist's Monthly Magazine, July) describes a new 

 spei ies 1 >f Sciarid fly, Plastosciara pemiciosa, the 

 larva? of which were found damaging cucumber roots 

 and stems in a nursery at West Worthing, where they 

 were present in very large numbers. 



Manganese in Plant Nutrition. — Since the dis- 

 covery of manganese in the soil and in plant ashes 

 by Scheele in 1774, numerous investigations have been 

 made on the occurrence, distribution, and probable 

 function of this element in its relation to agriculture. 

 In the July number of the Journal of the American 

 Chemical Society, Mr. J. S. McHargue, of the Kentucky 

 Agricultural Experiment Station, describes a careful 

 series of experiments, with purified materials (lack of 

 care in this respect having caused errors in previous 

 work), the results of which seem to point definitely 

 to the conclusion that manganese has a function to 

 perform in the production of chlorophyll, and con- 

 sequently in carbon assimilation and possibly in the 

 synthesis of protein. 



Formation of Marine Deposits above Sea- 

 level. — -The Report of the Secretary of the Smith- 

 sonian Institution for 1921 quotes some observations 

 made by Dr. Paul Bartsch at the south-east point of 

 Hanouma Bay, Hawaii, where he found a marine 

 flora and fauna living at a considerable elevation 

 (the precise height not given) above the level of the 

 sea. Alga?, molluscs, crustaceans, echinoderms, and 

 other marine organisms, says Dr. Bartsch, " occupy 

 pools and puddles kept moist and supplied with fresh 

 water by the spray from the breaking surf, which 

 incessanflv pounds that shore. I consider this 

 an important observation, since the occurrence of 

 fossiliferous lamina? bearing marine organisms between 

 sheets of lava has been held to indicate that they 



