February 8, 1894] 



NA TURE 



o:io 



versify Reporter for February 6, a very important proposal, 

 which may lead to a considerable increase in the number 

 of students resorting to Cambridge for advanced study or 

 research. The Council recommends that statutory powers 

 be obtained for the establishment of two new degrees, 

 Bachelor of Science and Bachelor of Letters, to be conferred 

 on graduates only, whether of Cambridge or of some recogni'^ed 

 University, British or foreign. The conditions suggested are 

 (i) matriculation, (2) residence for one academical year (three 

 terms), {3) evidence of advanced study or research in Cambridge, 

 (4) an original dissertation on some subject, literary or scientific, 

 coming under the cognisance of one of the Special Boards of 

 Studies. Hitherto only graduates of the Universities of Oxford 

 and Dublin, who have fulfilled conditions as to residence 

 equivalent to those in force at Cambridge, have been admissible 

 to ad eiDidem degrees. The new proposal is much more liberal, 

 and is calculated to attract some of those maturer students who 

 now, after graduating in their own University, seek op- 

 portunities for higher work in the continental school^. As 

 Cambridge graduates can qualify for the B. Sc. and B. Litt. 

 degrees only if they have passed one of the higher Honours 

 Examinations, and then only on submitting an approved 

 original dissertation, it is plainly intended that these degrees 

 shall imply a real distinction. It is interesting to note that 

 literary or scientific research, and not the faculty of passing 

 examinations, is a condition for the new " post-gnduate " 

 degree. At Oxford similar proposals are said to be afoot, and 

 if the two older Universities carry through their scheme, a great 

 step will have been taken towards making them once more the 

 resort of scholars from all parts of the world. 



The Times published on Tuesday a summary of the recom- 

 mendations of the Gresham Commission on a Teaching Univer- 

 sity for London, embodying a scheme for its constitution, with 

 visitor, chancellor, vice-chancellor, senate, academic council, 

 convocation, and schooU, and regulations as to examinations, 

 faculties, boards of studies, and degrees. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, December 14. — " x\ction of Light on 

 Bacteria. — Bacterial Photographs of the Solar and Electric 

 Spectra." By Prof. H. M. Ward, F.R.S. 



A thin film of gelatine or agar, in which spores or bacteria 

 are evenly distributed, is spread over the flat bottom of a 

 shallow glass dish. The lid of the dish is a plate of ground- 

 glass, in which one or more slots, about 5 inch wide and 

 2^ inches long, are pierced. The spectrum is so arranged that 

 the light-rays fall perpendicularly on the film carrying the 

 spores &c. , and can only reach the latter through the slots, all 

 other parts of the plate being covered by tin foil and black 

 paper. 



When the film has been thus locally exposed for a certain 

 number of hours to the spectral rays, the culture is put into the 

 incubator. All those parts protected from the light entirely, 

 behave as in any ordinary culture — the spores germinate out 

 and develop colonies, and the previou--ly transparent film 

 (transparent because the spores are too minute to afi'ect it) 

 becomes opaque. 



Under the slot, however, the spores were exposed to the 

 various rays of the successive regions of the spectrum. On one 

 part of the exposed area the infra-red rays fall ; on another the 

 red ; on another the orange ; and so on with the yellow, green, 

 blue, violet and ultra-violet rays. 



If any of these rays kill or injure the spores they fall on, 

 obviously the latter will show the effect by not germinating at 

 all in the incubator, after exposure, or by germinating more 

 or less slowly and feeby in comparison with the uninjured 

 spores. 



Wherever the spores do not germinate at all, the gelatine 

 remains transparent ; where they only germinate and develop 

 into slowly growing, feeble colonies, the transparency of the 

 gelatine film is merely clouded more or less ; whereas, where 

 they germinate and develop as vigorously as on the unexposed 

 parts of the film, the latter is rendered quite opaque. 



Obviously these diii'erences, or contrast effects, can be 



photographed, and the following is a photograph of a jilale 

 treated as described. 



■vr.-Uv 



m 





NO I 267, VOL. 40] 



In all cases so far examined, both the solar and electric 

 spectra show that no action whatever is perceptible in the infra- 

 red, red, orange, or yellow region, while all are injured or 

 destroyed in the blue and violet regions. 



The exact point when the action begins and ends is not the 

 same in all the experiments, though very nearly so, but it must 

 be reserved for the detailed memoir to discuss the various 

 cases. 



Broadly speaking, the action begins at the blue end of the 

 green, rises to a maximum as we pass to the violet end of the 

 blue, and diminishes as we proceed in the violet to the ultra- 

 violet regions. 



Some especially interesting results were obtained with the 

 electric spectrum. In the first place, the results with glass 

 prisms, lenses, &c. , were so feeble that it was necessary to 

 employ quartz throughout. 



Secondly, the bactericidal effect is found to extend far into 

 the ultra-violet. The intervention of a thin piece of glass 

 results in the cutting off" of a large proportion of effective rays. 



These results suggest evidently that the naked arc light may 

 prove to be a very efficient disinfecting agent in hospital wards, 

 railway carriages, or anywhere where the rays can be projected 

 directly on to the organism. 



January 25. — "The Effect produced upon Respiration by 

 Faradic Excitation of the Cerebrum in the Monkej% Dog, 

 Cat, and Rabbit." By W. G. Spencer. 



The effect upon respiration of exciting the cerebrum in a non- 

 ancesthetised animal is probably a complex one, yet, by careful 

 regulation of the anaesthetic state, four constant effects can be 

 obtained upon respiration by stimulation of the cortex, and 

 these can be traced down each in a course of its own from the 

 cortex to the medulla oblongata. 



A. Diminution of Action. 

 I. Slowing and Arrest oj the Respiratory Hhy thin. — The cor- 

 tical area where this result was obtained is situated just outside 

 the olfactory tract in front of the point where the tract joins the 

 temporosphenoidal lobe. On exposing successive and vertical 

 sectional surfaces of the hemisphere the same result was obtained 

 by exciting in the line of the strand of fibres known as the olfac- 

 tory limb of the anterior commissure. After decussating at the 



