August 4, 1892^ 



NATURE 



339 



at the posterior end of the body there is a series of delicate 

 dorsal and ventral processes ; these latter are segmentally ar- 

 ranged, developed in pairs upon the Ust sixty segments or so of 

 the body. There is no connection between the setae and these 

 processes, as in Bourne's Chastobranchus also found in the same 

 tank. This worm is referred to the Tubificidre, without having 

 any certain affinities to any of the known genera. — On the for- 

 mation of the germ-layers in Crangjn vulgaris, by W. F. R. 

 Weldon, MA. (i>lates xx. to xxii.). The author's conception of 

 the early development differs widely from that of Kingsley. 

 — On the pigment cells of the retina, by I. S. Boden 

 and F. C. Sprawson. The retinal pigment cells are 

 not, as usually represented, invariably hexagonal ; in speci- 

 mens taken from the eyes of sheep, ox, rabbit, kitten, pig, 

 hen, and frog, while hexagonal cells were the most numerous, 

 heptagonal cells were frequently found and scattA-ed at inter- 

 vals. Cells with tour, five, eight, nine, ten, and eleven sides 

 were found. — Observations upon the development of the seg- 

 mentation cavity, the archenteron, the germinal layers, and the 

 amnion in mammals, by Dr. Arthur Robinson (Plates xxiii. to 

 xxvii.). There is a general description of the development of 

 the ova of the rat and mouse up to the period of the comple- 

 tion of the blastodermic vesicle, and a comparison with the results 

 obtained by Fraser, Duval, and Selenka : there is a description 

 of the formation of the mesoblast and of the chorda dorsalis, 

 followed by a comparison of the ova of the rat and mouse with 

 the ova of other mammals and the lower vertebrates and by a 

 description of the formation of the amnion and a discussion of 

 the relation of amnion formation to "inversion," and by a de- 

 scription of the formation of the coelom. 



June. — Contains : — On the primitive segmentation of the 

 vertebrate brain, by Bertram H. Waters, B. A. (Plate xxviii.) ; 

 concludes that the fore-brain is composed of at least two well- 

 marked neuromeres, possibly of three ; that the mid-brain con- 

 sists of two neuromeres, from which there is every reason to think 

 that the third and fourth nerves take their origin, and hence 

 these deserve to be recognized as se^^mental structures ; and that 

 the hind brain consists of six neuromeres. On the oscula and 

 nr\3.\.omy oi Leucosolenia clathrus, O. S., by E. A. Minchin, B.A. 

 (Plate xxix.). In this sponge, in the fre-h and healthy condi- 

 tion, not only are there oscula, "but in the full-sized specimens 

 larger oscula than in any other Leucosolenia known to me, 

 whether from pictures or in the flesh." These oscula are pro- 

 vided with a sphincter, and can be so tightly closed 

 as to escape notice. Iloeckel's four varieties of the sponge 

 are only different states of contraction. — Researches into 

 the embryology of the OHgochaeta, No. i : on certain 

 points in the development of Acanthodrilus initUiponis, 

 by Frank E. Beddard, M. A. (Plates xxx. and xxxi. ). — 

 On the Innervation of the Cerata of some Nudibranchiata, by 

 Dr. W. A. Ilerdmin and J. A. Clutt (Plates xxxii. toxxxiv.). If 

 the cerata of Nudihranchs cannot all be said to be true epipodia 

 innervated by the pedals, it would seem equally impossible to 

 regard them in all cases as pallial outgrowths supplied by the 

 pleural ganglia. It is possible that they may have been epipodial 

 in origin, although there be now, in some, a connection with 

 pleural nerves. — Notes on Elasmobranch development, by 

 Adam Sedgwick, M.A. (Plate xxxv.). On the paired nephridia 

 of Prosobranchs, the homologies of the only remaining nephri- 

 dium of most Prosobranchs, and the relations of the nephridia 

 to the gonad and the genital duct, by Dr. R. v. Erlanger 

 {Plates xxxvi. and xxxvii.). 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society. June i6. — "The Physiological Action of 

 the Nitrites of the Paraffin Series considered in connection with 

 their Chemical Constitution. Part II. Action of the Nitrites 

 on Muscular Tissue and Discussion of Results." By J. Theo- 

 dore Cash, M.D., F. R.S., Professor of Materia Medica in the 

 University of Aberdeen, and Wyndham R. Dunstan, M.A., 

 Professor of Chemistry to the Pharmaceutical Society of Great 

 Britain. 



Continuing the examination of the physiological action of 

 various pure organic nitrites of the paraffin series (Part I. ; 

 Roy. Soc. Proc, 1891), the authors have studied their effect on 

 striated muscular tissue. When the vapours of these nitrites 

 come into contact with the muscle a paralysant effect is observed. 

 All the experiments were made with the triceps and gastrocne- 



NO. II 88, VOL. 46] 



mius of Rana temporaria. The muscle was contained in a 

 specially constructed air-tight chamber. A very extensive series 

 of experiments was necessary in order to obtain reliable con- 

 trasts. The amounts of the nitrites employed varied between 

 jV and :iiir c.c. 



Several series of concordant results have thus been obtained 

 which lead to two different orders of activity, viz. (i) with refer- 

 ence to the extent to which equal quantities of nitrites shorten 

 the resting muscle, and (2) with reference to the rapidity with 

 which the shortening is produced. The order of activity of the 

 nitrites as regards the extent of the shortening they induce is as 

 follows :— (i.) Iso butyl, (ii.) tertiary amyl, (iii.) secondary 

 butyl, (iv.) secondary propyl, (v.) propyl, (vi.) tertiary butyl, 

 (vii.) butyl, (viii.) o-amyl, (ix.) /3 amyl, (x.) ethyl, (xi.) methyl. 

 The order representing the speed with which shortening occurs 

 is(i.) methyl, (ii.) ethyl, (iii.) secondary propyl, (iv.) tertiary 

 amyl, (v.) primary propyl, (vi.) tertiary butyl, (vii.) secondary 

 butyl, (viii.) a-amyl, (ix.) 3-amyl, (x.) primary butyl, (xi.) iso- 

 butyl. 



The effect of these nutrites in interfering with the active con- 

 traction of a stimulated muscle has also been studied, and it has 

 been ascertained that very minute doses, insufficient to cause 

 passive contraction, interfere in a marked degree with the active 

 contraction, and cause the muscle to fail in responding to stimu- 

 lation, whilst the companion muscle, contained in a closed 

 chamber free from nitrite vapour, st 11 responded to stimulation. 



The remainder of the paper is devoted to a discussion of the 

 connection between the various phases of physiological action 

 and the chemical constitution of the nitrites which gave rise to 

 them. The principal conclusions which have been arrived at 

 are briefly as follows : — The physiological action of these nitrites 

 is not solely, and in some cases not even mainly, dependent on 

 the amount of nitroxyl (NOj) they contain. 



In respect of all pha-es of physiological activity, the secondary 

 and tertiary nitrites are more powerful than the corresponding 

 primary compounds. This is to be chiefly attributed not to the 

 direct physiological action of the secondary and tertiary groups, 

 but to the great facility with which these compounds suffer de- 

 composition mainly into the alcohol and nitrous acid. In respect 

 of the acceleration of the pulse, the power of the nitrites is 

 directly as their molecular weight, and inversely as the quantity 

 of nitroxyl they contain. They, therefore, fall into an order of 

 physiological activity which is identical with that in which they 

 stand in the homologous series. This same relationship holds, 

 though less uniformly, in their power of reducing blood-pressure, 

 and of inducing muscular contraction. 



This order appears to be the result not so much of the direct 

 physiological influence of the substituted methyl groups as of the 

 increased chemical instability which their presence confers on the 

 higher members of the series. In respect of the duration of sub- 

 normal pressure, as well as of the rapidity with which muscular 

 contraction ensues, the activity of the nitrites is expressed by an 

 order which is for the most part the reverse of that representing 

 their power in accelerating the pulse, reducing blood-pres-ure, 

 and contracting muscular fibre, this order being in general con- 

 trary to that of the homologous series. In these respects the 

 more volatile nitrites of low molecular weight which contain 

 relatively more nitroxyl are the most active. It appears probable 

 that these .simpler nitrites more readily attach themselves to 

 certain constituents of blood and muscle, and thus act more 

 quickly than the higher compounds, whilst their greater stability 

 causes their effects, i.e., reduction of blood- pressure, &c., to 

 endure for a greater length of time than that of the higher and 

 more easily decomposed bodies. 



A large proportion of an organic nitrite is changed into nitrate 

 in its passage through the organism, and is excreted as an alkali 

 nitrate in the urine. 



The results which have been gained by this research have an 

 important bearing on the therapeutic employment of the nitrites. 

 It is proposed elsewhere to consider what the outcome of this 

 investigation is for practical medicine. 



Paris. 

 Academy of Sciences, July 25. — M. d'Abbadie in the chair. 

 — Some new observations on the employment of the calori- 

 nietric shell, by M. Rerthelot. Different bodies must be treated 

 differently, according as they are fixed, volatile, or gaseous. For 

 fixed compounds, solid or liquid, the ratio between the weight 

 of the combustible and the weight of oxygen ought to be such 

 that the gas which remains after combustion contains at least 60 



