NATURE 



!79 



THURSDAY, DECEMBER 



igi; 



THE METABOLISM OF LEPIDOPTEROUS 



PUP.E. * 



Die Assimilationstcitigkcit bci Schinetterlings- 



Puppen. By Prof. Grafin von Linden. Pp. 



164 + iii Taf. (Leipzig: Veit and Co., 1912.) 



Price 4.50 marks. 



THE phenomena of insect metamorphosis 

 have been widely studied in this country 

 from the point of view of morphology ; the physio- 

 logical aspects of the process have in comparison 

 met with little attention. Several foreign ob- 

 servers have devoted themselves to the investiga- 

 tion of various questions relating to the exchange 

 of material during growth and development in 

 insects, the species usually selected being the 

 common silkworm-moth of commerce. Results 

 of considerable interest have followed from these 

 researches ; and, as the author of the treatise 

 before us remarks, a wide field is thereby opened 

 for further physiological investigation. 



Tlie Grafm von Linden has put together in con- 

 nected form the outcome of her own experiments, 

 conducted from 1906 to 191 1, on gas-exchange in 

 lepidopterous pupae. To these records she has 

 added an account of the investigations of other 

 workers, summarising the whole in a concluding- 

 chapter, and giving her own interpretation of the 

 facts and figures derived from these various 

 sources. 



The species experimented on by the author 

 were the "scarce swallow-tail" [Papilio poda- 

 liritis), the spurge hawk-moth {Sphinx euphorbiae), 

 the pine eggar {■Lasiocampa pini), the small tor- 

 loiseshell (Vanessa wticae), and the "srhall mag- 

 pie " (Botys urticata). In all these it was found 

 that in an atmosphere charged with COo, COj 

 was absorbed and O., might be given off. The 

 insect, like the plant, uses light-energy to bring 

 about the decomposition of CO, and the conse- 

 quent liberation of oxygen. It was also found 

 that under similar conditions the pupae could take 

 up nitrogen from the air, and thus increase their 

 nitrogenous constituents. The insects experi- 

 mented upon took up from the atmosphere, ac- 

 cording to the author, carbon, nitrogen, 

 hydrogen, and oxygen, and, even when no other 

 source of nutriment was open to them, they were 

 thus able, not onh' to repair loss caused by 

 respiration, but also to build up new organic sub- 

 stances. This, she remarks, recalls the assimila- 

 tory process in plants. The resulting materials 

 were protein, fat, and carbohydrates. 



Of external influences favouring the absorption 

 of COj, ligfht, especially the rays of low refrangi- 

 NO. 2249, VOL. 90] 



bility, is the principal in insects as in plants. Tem- 

 perature has also a strong influence. High tem- 

 peratures stimulate the respiratory process, so 

 much so that even under otherwise favourable 

 conditions of light the assimilatory process is 

 masked. Another important factor is the degree 

 of CO, concentration in the atmosphere, a high 

 amount of CO, in the air hindering, especially in 

 active larvae, the respiratory process, and corre- 

 spondingly favouring assimilation. Lastly, the 

 humidity of the atmosphere has a strong effect in 

 promoting CO, absorption. 



The Grafin's results on the assimilation of 

 atmospheric nitrogen are of special interest to 

 physiologists. In almost all her experiments vi.h 

 pups a taking up of nitrogen was observed ; in 

 larvae, an alternate taking up and giving out. 

 Where there was a regular assimilation of 

 nitrogen it was dependent on light; the same 

 occurred in plants. This, she says, seems strik- 

 ing, in view of the fact that most plant-physiolo- 

 gists deny assimilation of atmospheric nitrogen 

 except by the help of bacteria. But it is less 

 remarkable in the case of pupa, because the ab- 

 sorption of nitrogen is already known to take 

 place under starvation in very diverse animals 

 (Regnault and Reiset). 



The author believes that not only in an artifi- 

 cially COg-laden atmosphere, but also under 

 normal conditions, the assimilation of COg by 

 pupae may take place; supporting this view by 

 citation of the results obtained by Kellner, Urech, 

 Dubois, Couvreur, and others. Space will not 

 permit of a full statement of her conclusions, 

 which are certainly unexpected, and in some parti- 

 culars revolutionary. Certain obvious criticisms 

 must also be forgone. But her treatise is an 

 arresting one, and the subject undoubtedly calls 

 for fresh investigation. F. A. D. 



SYLVESTER'S MATHEMATICAL PAPERS. 

 The Collected Mathematical Papers of James 



Joseph Sylvester, F.R.S. Vol-, iv. (1882-97). 



Pp. xxxviii + 756. (Cambridge Liniversity 



Press, 1912.) , iSi'. net. 



THE longest items in this final volume are the 

 "constructive theory of partitions," pub- 

 lished in The American Journal, and the lectures 

 on reciprocants. The first of these is more con- 

 secutive than the notes on Sylvester's King's Col- 

 lege course printed in a previous volume; perhaps, 

 for this very reason, it is not quite so in- 

 teresting. But his use of graphs is most 

 ingenious, and tlie occurrence of Farey series in 

 this connection may be specially noted. It is a 

 rather curious fact that at the end of Art. 17 (pp. 

 15-16), Sylvester says that he has not pro\ed a 



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