1896. NOTES AND COMMENTS. 155 



actual photographs are no more than the shadows thrown by the 

 substances which are opaque to the rays. To secure clearness of 

 outline, it is therefore necessary that the photographic plate should 

 be very close to the object from which shadows are desired. For 

 instance, it would be very desirable to obtain magnified shadow- 

 pictures of the small bones in the wrist and ancle of many animals, 

 before these had been disturbed by disarticulation. But lenses of all 

 substances that have been employed fail to focus the rays. As usual 

 with a new discovery, the newspapers swallow with avidity a number 

 of extraordinary suggestions and additional applications. It is tele- 

 graphed from Rome that one Professor Salvioni, of Perugia, has 

 invented an instrument, the application of which to the eye " enables 

 the vision by means of the Roentgen rays to penetrate opaque bodies. 

 The retina of the eye is impressed by means of this ' cryptoscope ' 

 exactly in the same way as a photographic plate." Of course the 

 newspapers may be maligning Professor Salvioni, but it is needless to 

 say that, as the photographs taken by the new method are the result 

 of transmitted — not reflected — -light, it would be a wonderful instrument 

 indeed that enabled the eye to penetrate opaque bodies. Professor 

 Edison, too, is well to the fore. Apparently he has abandoned his 

 designs for destroying the British navy by electrified water, and is 

 now turning his attention to photographing the living brain by means 

 of the new rays. In this invention he will have to produce a newer 

 kind of ray. For the living human brain is enclosed in a bony box, 

 and Professor Roentgen's rays have achieved their celebrity by failing 

 to penetrate bone. But the suggestion we like best is that of a French 

 lady, writing to a French journal. She has realised that the new rays 

 penetrate clothing, and she proposes that women should combine 

 against the immorality of modern photography. 



Danish and German Science. 



We have had on our table for some time three publications with 

 titles that are somewhat formidable to English readers. These are : 

 (i) Forelobig Meddelelse om Spiraclerne hos Insecterne i Alminde- 

 lighed og hos Scarabaeerne i Saerdeleshed m. m. til Paaviisning af 

 hvad dermed tilstraekkelig Dristighed kan udgives for Natur- 

 videnskab. En literair og zoologisk Undersogelse ved William Sorensen, 

 Kjobenhavn i Juli 1895. (2) I Anledning af Dr. W. Sorensens 

 " Forelobig Meddelelse om Spiraclerne hos Insecterne " o.s.v. Af 

 J. E. V. Boas, Kobenhavn, 1895. (s) Gernianisering af Dansk Viden- 

 skab. Ved Dr. H. J. Hansen, Kjobenhavn, 1895. 



These three essays contain the attack, reply, and rejoinder in 

 a sharp personal controversy. The names of the authors are a 

 guarantee that the reader will neither find the subject-matter unim- 

 portant nor the handling of it trivial. We do not propose here to 

 enter into the merits of the principal question. They need to be 



