July II, 1878] 



NATURE 



293 



those of type III. ; if this colour was visible in stars of 

 the other two types, they were always near the horizon. Yellow 

 was rarely absent ; yellow of greater or lesser brightness pre- 

 dominated completely in a large number of stars when they were 

 high above the horizon and had ceased to scintillate. Orange is 

 very frequent aniongst the colours of the stars of the third type, 

 while they scintillate. 



If we reflect upon this short sketch of the changes of colour of 

 scintillating stars, we see at once how complicated this pheno- 

 menon is, and that, in order to obtain data of tolerable certainty, 

 at least two series of observations must be made, one in dry and 

 the other in rainy weather ; and further, that the influence of the 

 star's altitude must be determined, which can be done by dividing 

 the observations into separate zones of five degrees each. 



With regard to the colours of scintillating stars Arago has 

 expressed the opinion that the colour observed at any special 

 moment is the complementaiy colour to those rays of the light 

 peculiar to the scintillating star which at that moment are absent 

 in the eye or in the telescope. M. Montigny agrees with this 

 view and confirms it by an observation which he made when, on 

 some evening specially favourable for observation, he inserted a 

 prism just when the circle produced in the scintillometer by the 

 light of the star Capella was very sharp and showed bright 

 colours ; he then found the two arcs of the circle divided 

 into different colours, and this could not have been the case if 

 the colours seen without the prism had actually been present. 

 M. Montigny, however, intends further to examine this question 

 by means of the spectroscope. 



Arago also raised the v.ell-known question whether the scin- 

 tillation of stars is the same for two observers stationed at 

 different places. M. Montigny replies to this question in the 

 negative, and this was Arago's opinion also; he found the 

 coloiu-3 of a star to be diflferent for those rays which are differ- 

 ently refracted by the two halves of the object-glass. In the 

 same sense M. Bonders has noticed that the scintillation does 

 not always show the same peculiarities for each eye of the same 

 observer. Another circumstance may be cited here as another 

 pfoof, viz., that a double star, both components of which are of 

 the same colour, such as Castor and its companion, which are 

 both white, does not always show the same colours in the scin- 

 tillometer at the same angles of position. Although the angle 

 separating these two stars amounts to but five seconds of arc, it 

 yet suffices to produce different colours. This shows how greatly 

 the appearance of stars in the scintillometer is affected by the 

 smallest differences in the conditions under which they are 

 observed, since two separate pencils of rays of the same colour 

 ti^velling side by side and at the same moment may yet be 

 changed to different colours on their passage through the 

 atmosphere. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



The subject of the use and abuse of examinations is begin- 

 ning to be agitated in Austria. Within a few weeks past, two 

 students, one at Pest and the second at Graz, have committed 

 suicide after failing to pass examinations for the doctor's degree. 

 The latter of the two had completed a lengthy course of study, 

 and was an assistant of recognised ability in the university. 



During the past few years the educational institutions of 

 Rome have been entirely reorganised. The university, as con- 

 stituted at present, is without a theological faculty. It numbers 

 sixty-four professors, twelve in the legal faculty, twenty-four in 

 the medical, sixteen in the scientific, and twelve in the philo- 

 logical-philosophical. Nearly all the conveniences of a well- 

 appointed university are now enjoyed by the students : a botani- 

 cal garden, laboratories for physics, chemistry, and physiology ; 

 the new observatory on the Capitoline, with special institutes 

 for geology, mineralogy, mathematical physics, pharmacy, com- 

 parative zoology and anatomy, pathological anatomy, and six 

 clinics. During the past nfbnth the Minister of Education has 

 issued a decree for the foundation of a school of archseology, 

 which shall be amply equipped, and meet a want long felt in 

 this centre of archaeological investigation. 



SOCIETIES AND ACADEMIES 



London 



Royal Society, May 23.— "Experimental Results relating 



to the Rhythmical and Excitatory Motions of the Ventricle oi 



the Heart of the Frog, and of the Electrical Phenomena which 



accompany them," by T. Burdon Sanderson, M.D., F.R.S.. and 

 P. J.M.Page, B.Sc, F.C.S. 



This paper, although of some length, is a condensed state- 

 ment of experimental results, so that it scarcely admits of being 

 abstracted. These relate, as stated in the first paragraph, to (l) 

 the order and duration of the rhythmical and excitatory motions 

 of the heart of the frog, (2) the normal electrical condition of 

 the surface of the heart and the influence thereon of mechanical, 

 chemical and thermal injuries, and {3) the characters of the 

 normal and of the excitatory electrical variations, and the modi- 

 fications of those characters which are induced by injuries of the 

 surface, and under the temporary influence of radiant heat. As 

 we have not space to reproduce the whole, we will confine our- 

 selves chiefly to the very interesting experiments contained in 

 the two last sections. 



The authors begin this part of the subject with the statement 

 that they have confirmed, by repeated experiment, the observa- 

 tions made by Engelmann in 1873, that all parts of the surface 

 of the "resting" heart are equipotential, and that the electrical 

 inequalities which are usually found whenever the surface of 

 the organ is investigated, when in this condition, owe their 

 existence to slight injuries ; they then proceed to discuss the con- 

 ditions which lead to the existence of electrical diflferences. 

 These are (i) permanent injury of the surface, however super- 

 ficial and slight in extent, and (2) the temporary influence of 

 radiant heat. As" regards permanent injury, their observa- 

 tions are substantially in accordance with the conclusions of 

 Hermann as regards other excitable and contractile tissues, viz., 

 that the death of a part renders it negative to all living parts of 

 the same organ. Substituting for the word death (which, in 

 order to express the whole truth, must be understood to include 

 every degree of local lesion, however limited in extent or slight 

 in degree) the expression "permanent injury," this proposition 

 becomes adequate for its purpose. 



The authors further find that the influence of radiant heat 

 produces a modification of the electrical condition of a part, of 

 which the sign is opposed to that of the electrical change pro- 

 duced by injury. They were led to this result by the considera- 

 tion that if arrest of the chemical changes which constitute the 

 life of a part renders it negative, it is probable that a momen- 

 tary intensification of these changes will render it positive. 



The fundamental experiment by which both facts are estab- 

 lished is as follows : — Two points on the surface of the heart, 

 which may be as near to each other as two millims., are con- 

 nected with a galvanoscopic circuit, and found to be equi- 

 potential. A loop of platinum wire, heated by a ciurent, is 

 brought into the neighbourhood of one of them for one second. 

 After an interval of about a second the warmed surface becomes 

 positive : in a few moments this effect subsides. If, then, the hot 

 wire is brought nearer so as to scorch the siu-face, however 

 slightly, and then removed, the opposite effect — that of per- 

 manent injury — manifests itself. The same spot, wliich was 

 before positive, now becomes negative in a very much greater 

 degree; for whereas the temporary "positivity" scarcely ex- 

 ceeds l-2,oooth Daniell, the "difference" of potential produced 

 by injury may amount to 3-iooths Daniell. On the physio- 

 logical meaning of these effects the authors do not enter. An 

 indication of their bearing is, however, given by the observation 

 in the next section, which relates to the so-called variation of 

 the heart. By variation is meant the electrical disturbance 

 which accompanies, or rather precedes, each contraction of the 

 ventricle. The fact that such a disturbance exists has been 

 known for several years. It has also been recognised that it 

 precedes the visible change of form by which the systole dis- 

 closes itself. The authors now show that the disturbance con- 

 sists of two phases having opposite signs — that in the* first 

 phase, which is of short duration, parts near the apex become 

 positive to parts further from it ; that in the second phase the 

 opposite condition is observed ; further, that the first phase is 

 entirely over before the ventricle begins its contraction, whereas 

 the second phase corresponds in duration with the period during 

 which the ventricle is doing the greatest amount of mechanical 

 work, and ceases at the moment of decline of the muscular con- 

 traction of the ventricle. These time relations of the two 

 phases suggest the inference that in all probability the first 

 phase corresponds with that of the negative variation of ordi- 

 nary muscle, with which it agrees in sign, and that the second 

 phase is more immediately associated with the muscular con- 

 traction. That this is so appears to be shown by the observa- 

 tion that if any two points of the rhythmically pulsating heart 

 a and b, of which a is nearest to the apex, are investigated by 



