374 NATURAL SCIENCE. June, 



process can be relied upon by surgeons. We learn also from this 

 journal that Dr. Macintyre, of Glasgow, who was the first to complete 

 the skiagraphic survey of the body of an adult, has proved that it is 

 quite possible to skiagraph the bones of the skull, and to show very 

 complete details of its structure. " This is rendered possible by the 

 fact that the thickness of the head allows considerable dispersion of 

 rays, so that the varying structure of the side of the skull furthest 

 from the dry plate causes no definite shadow at all, while the one 

 that is nearest to the plate gives a perfectly sharp image, full of 

 detail of the bone-structure." At the Royal Society's soiree many of 

 the visitors amused themselves by studying their own skeletons with 

 the aid of the apparatus exhibited by Mr. A. A. C. Swinton and 

 Mr. Herbert Jackson. 



It is, however, the applications of this process to zoology that 

 are of more interest to our readers. At the meeting of the Zoological 

 Society on May 5, Mr. W. E. Hoyle exhibited a remarkably fine 

 skiagram of a snake in the act of swallowing a mouse ; but, unfortu- 

 nately, the most remarkable point about it was that the snake was a 

 grass snake, which never touches mammals, but only such cold- 

 blooded prey as frogs and lizards. Mr. G. A. Boulenger, who followed 

 with a paper on some Batrachians from the Caucasus, has been one 

 of the first to use the X-rays for purposes of systematic zoology. In 

 studying the new toad, Pelodytes caucasicus, which is only the second 

 species of the genus known (the other, Pelodytes punctatus, being 

 confined to Western Europe), skiagrams had enabled him to determine 

 all the more important points in the structure of its skeleton. The 

 value of the application of this method lies in the fact that only a 

 single specimen of the species is known, and this, being in the British 

 Museum, cannot be cut up to determine its osteological characters. 

 In this particular case, moreover, these characters are of much 

 significance, one of them, the junction of the calcaneum with the 

 astragalus, occurring in Pelodytes alone among the Anoura ; this 

 peculiarity is clearly shown in the photograph, as also are the form 

 and extent of the fronto-parietal fontanelle, the shape of the 

 enormously-expanded sacral transverse processes, and the direction 

 of those in the lumbar region. Here, too, we may refer to a skiagram 

 of Astropecten irregularis sent to Nature by Mr. Alexander Meek. The 

 more interesting features shown by it are the various food-bodies and 

 their position in the stomachic caeca. 



Experiments made by W. G. Miller, of Kingston, Ont., and 

 published in the American Geologist for May, p. 324, seem to show that 

 the X-rays may prove an aid also to the petrologist and mineralogist, 

 though they will hardly supplant polarised light. Botanists and 

 palaeontologists have not as yet shown any eagerness to adopt this 

 method : we suggest it to the disputants over Archaopteryx, as no less 

 efficacious than controversial personalities. 



The most striking of all the exhibits at the Royal Society's 



