478 



NA TURE 



[March 19, 1896 



of special interest. About the general habits of this fish, he 

 thinks it unnecessary to write much, as Fiilleborn's notes, so 

 recently published, are but confirmed ; but we are glad that he 

 has added some on the breeding habits, which are illustrated 

 with sketches of the nest and of the cloud of young fry attended 

 by the male. The author concludes that the early development 

 must certainly be regarded as furnishing abundant evidence of 

 intermediate characters ; to the Ganoids, on the one hand, and 

 to the Teleosts, on the other. These ontogenetic nearnesses 

 become, accordingly, of the greatest interest, since they confirm 

 the results of the structural study of recent and fossil forms upon 

 the Amioid descent of Teleosts. — On Kynotus cingtdatus, a new 

 species of earthworm from Imerina in Madagascar, by W. 

 Blaxland Benham (Plates 33 and 34). This interesting species 

 is remarkable for the great number and small size of the 

 segments composing the body ; there were three anterior portions 

 sent for examination, each about 225 mm. in length ; each piece 

 consisted of some three hundred or more segments ; the whole 

 worm being probably about 450 mm. to 500 mm. in length ; it 

 possesses a clitellum of relatively enormous dimensions, with most 

 peculiar "claspers."^ — Notes on the ciliation of the ectoderm 

 of the amphibian embryo, by R. Assheton (Plate 35), 

 describes the distribution of the cilia over the surface of the 

 bodies of the tadpoles of Rana tentporaria and Triton cristatiis. 

 As the author notes, the existence of a ciliated embryo among 

 craniate vertebrates seems often to be overlooked. — On the 

 ontogenetic differentiations of the ectoderm in Necturus 

 (Study II.). — On the development of the peripheral nervous 

 system, by Julia B. Piatt (Plates 36-38). Even if we assume 

 Necturus to be a monotypic genus, it would have been advisable 

 for the authoress to have cited a specific name for the 

 Batrachian, whose peripheral nervous system she has so 

 painstakingly elaborated. The summary, occupying two pages, 

 is too long to be cited, and does not admit of being further 

 condensed ; we note that "although delicate protoplasmic 

 prolongations connecting cell with cell initiate the specialised 

 coordination of the nervous system, a common reticulum, such 

 as Sedgwick describes, into which nuclei migrate, does not exist 

 in Nechirtis'". {lateralis']. This number contains a title and index 

 to Volume xxxviii. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, February 13.— "On the Behaviour of 

 Argon and Helium when submitted to the Electric Discharge." 

 By Dr. J. N. Collie and Prof. William Ramsay, F.R.S. 



Some years ago, Natterer published the results of experiments 

 on the passage of electricity through various gases and vapours 

 at the ordinary atmospheric pressure ; he found that the length 

 of the spark, or the "spark-gap " varied in length in a manner 

 approximately proportional to the number of atoms in the 

 molecule of the gas ; thus in mercury gas the distance was very 

 much greater than that obtained in hydrogen, oxygen, nitrogen, 

 or other diatomic gases ; and in these, the spark-gap was longer 

 than in substances of more complex molecular constitution. 



Experiments of a similar nature, carried out by us on some 

 common gases and on argon and helium, gave the results which 

 are summarised in the following table : — 



Oxygen ... 

 Air 



Hydrogen 

 Argon 

 Helium ... 



mm. 



23-0 



33-0 



39"o 



45*5 



Probably 250 or 300 



The current was of constant potential and quantity ; and the 

 hammer of the coil was kept in a constant position during the 

 experiments. Indeed, on re-testing the spark-gap with air, 

 after the experiments were finished, the original number was re- 

 produced. 



On lowering pressure, this spark-discharge changes into a 

 nbbon-like discharge, before the "fluffy" appearance of a so- 

 called vacuum tube becomes visible. It appeared that this 

 •change, occurring at a definite pressure, might be measured with 

 fair accuracy. The results of a series of such experiments is to 

 show that the character of the discharge changes for the under- 

 mentioned gases at the pressures stated : — 



mm. 



Air 73 or 74 



Hydrogen ... 42 „ 43 



Oxygen 81 



NO. 1377, VOL. 53] 



Carbon dioxide 

 Cyanogen ... 

 Nitrogen 

 Carbon monoxide 

 Helium 



mm. 



92 or 94 



23 



- 33 



49 



1270 



A tube filled with helium shows all the phenomena of a vacuum 

 tube when containing the gas at atmospheric pressure. 



The visibility of the spectrum of one gas in presence of another 

 was next investigated. For a full description of the method 

 of filling the tubes, and altering the pressure, the original paper 

 must be consulted. Only the final results are here reproduced. 



Amount of Gas detectable in a Mixture. 

 Per cent, 

 (i) Helium in hydrogen 33 of helium invisible at 2"6i mm. 

 lO'9 ,, barely visible at the 



lowest pressure. 

 O'ooi visible at all pressures. 



(2) Hydrogen in helium 



(3) Nitrogen in helium 



(4) Helium in nitrogen 



(5) Argon in helium 



(6) Helium in argon 



(7) Nitrogen in argon 



(8) Argon in nitrogen 



(9) Argon in oxygen 



o"oi almost invisible. 

 10 of helium difficult to detect. 

 0'o6 still visible at all pressures. 

 33 invisible at 2 '62 mm. pressure. 



25 „ 2-58 „ 



0-42 „ 17 M 



o-o8 „ o-i8 ,, 



though just visible at I '05 mm. 

 37 barely visible at any pressure. 



2 '3 difficult to distinguish at i'04 

 mm. pressure. 

 From these experiments it appears that at high pressures, a dis- 

 charge passes much more readily through helium thajn through 

 other gases ; but at a low pressure, if passage of current can be > 

 inferred from luminosity of spectrum, all other gases convey I 

 current more readily than helium does ; and nitrogen conveys ■| 

 current more readily than argon. This is probably connected 

 with the known fact that decrease of pressure promotes dissocia- 

 tion. The experiments on the relative luminosity of these gases 

 were made with electrodeless tubes, hence it cannot be objected 

 that the passage of current is determined by the attraction of the 

 material of the electrodes for the gas under experiment. 



"On the Absorption of the extreme Violet and ultra- Violet 

 Rays of the Solar Spectrum by Haemoglobin, its Compounds 

 and certain of its Derivatives." By Dr. Arthur Gamgee, F.R.S. 

 Emeritus Professor of Physiology in the Owens College, Victoria, 

 University. 



The investigation, of which the chief results are communi- 

 cated in this paper, had for its starting-point the observation 0% 

 the late Prof. J. L. Soret, of Geneva, who showed that, it 

 addition to the absorption bands in the visible spectrum, solu-^ 

 tions of the blood-colouring matter are characterised by an in- 

 tense absorption band in the extreme violet between G and H. 

 The present research has been conducted with the aid of photo- 

 graphy, quartz prisms and lenses being employed. 



The following are some of the principal results of the investi- 

 gation :- 



I. The compounds of haemoglobin with oxygen, carbonic 

 oxide, and nitric oxide present, even in highly dilute solutions, 

 an absorption band between Fraunhofer's lines G and H. Ir> 

 the case of oxy-haemoglobin the mean ray absorbed coincides 

 with A 414-0, that is to say, the centre of absorption is slightly 

 nearer the red end of the spectrum than Soret had stated ; this 

 observer placed the centre of absorption at h{\A,\o-\). As 

 Soret had indicated, in the case of the compound of carbonic 

 oxide with haemoglobin, the absorption band is slightly dis- 

 placed towards the less refrangible end of the spectrum. The 

 combination of haemoglobin with nitric oxide presents an ab- 

 sorption band occupying precisely the position of that of the 

 CO-compound. In the case of these two compounds, the mean 

 ray absorbed corresponds to A420'5. 



II. When the molecule of dissociable oxygen is removed from 

 oxy-haemoglobin, either by the action of reducing agents, ox by 

 boiling in vacuo, the absorption band in the extreme violet is 

 remarkably displaced towards the less refrangible end of the 

 spectrum, the centre of absorption corresponding to A. 426 'o. 



III. The absorption of the extreme violet depends on the 

 iron-containing moiety of the haemoglobin molecule, for, 

 whereas it is not presented by the albuminous product of the 

 decomposition of the blood-colouring matter, it is characteristic 

 of the acid compounds of haematin and of hasmochromogen. 



