306 



SCIEH^CE. 



[Vol. IX., No. 316 



The succeeding chapters give us an account of 

 the author's elaborate photographic study of the 

 solar and metallic spectra, a fuller statement and 

 discussion of the dissociation hypothesis, and a 

 comparison of it with certain test-experiments 

 and with the observations that have been made 

 upon the spectra of sunspots and of the chromo- 

 sphere. 



The twenty-fifth chapter deals with the results 

 deduced from the observations of recent eclipses ; 

 the twenty-sixth is devoted to the 'basic lines,' to 

 which the author still clings with something like 

 a parent's tenderness for a feeble child ; the 

 twenty-seventh deals with the spectroscopic phe- 

 nomena of the electric arc ; and the twenty-eighth 

 and final chapter gives a sort of summing-up and 

 general application of the hypothesis to the phe- 

 nomena of solar physics. 



As to the ' basic lines,' which if really existent 

 would amount to something hardly short of a 

 demonstration of the dissociation hypothesis, the 

 author frankly concedes that the apparent coinci- 

 dences between the lines of different metals are 

 not exact when examined with sufficient disper- 

 sion, but he maintains that the near approach to 

 coincidence is hardly less significant, and ap- 

 peals to the observations of lines affected in the 

 spectra of sunspots and prominences to show that 

 the ' basic lines ' are essentially different from 

 other lines. It is certainly true, that, as compared 

 with other lines, these ' basic lines ' are observed 

 with very disproportionate frequency and inten- 

 sity ; but to most spectroscopists it appears that 

 asufficient explanation exists in the fact that each 

 of them is double or multiple, having each of the 

 components separately affected. In most cases 

 the thickening or reversal of a line is a very deli- 

 cate phenomenon, difficult to make out at best ; 

 and, when two or more such lines happen to stand 

 close together, they catch the eje more readily : 

 probably that is all. 



Taking the whole work through, it may be said, 

 that, while here and there passages are open to 

 obvious criticism and objection, Mr. Lockyer un- 

 doubtedly makes out a strong case in tavor of his 

 'dissociation hypothesis' by showing its accord- 

 ance with the phenomena of the solar and stellar 

 spectra. At the same time the alternative hypoth- 

 esis that an elementary molecule, without break- 

 ing up, may, after the analogies of allotropism, 

 be capable of very different modes of vibration 

 under different circumstances of pressure, den- 

 sity, and temperature, and so give entirely 

 different spectra, — this hypothesis seems equally 

 reconcilable with observed facts. And it does not 

 encounter the difficulties, which Mr. Lockyer 

 barely alludes to, that our present chemical ele- 



ments seem to be set apart from all compound 

 bodies by Dulong and Petit's law of atomic heats, 

 and Mendeljeff's periodic series. Until this diffi- 

 culty is overcome, — we do not mean to imply 

 that it is necessarily insurmountable, — we doubt 

 whether most physicists and chemists will be dis- 

 posed to abandon entirely the hypothesis of 

 ' multiple spectra' for that of ' dissociation." 



Peofessor Leidy, in the Journal of comparative 

 medicine and surgery, communicates his observa- 

 tions on the subject of tape-worms in birds. He 

 finds that birds are as much infested with intes- 

 tinal worms as other classes of animals, and that 

 none appear to be exempt, no matter what may 

 be the nature of their food, though aquatic birds 

 appear to harbor a greater number of species, as 

 exemplified by' ducks and geese. Among the 

 parasites, tape-worms — mostly of the genus Tae- 

 nia — are common, though less so than the thread- 

 worms. The domestic fowl in Europe has been 

 reported to harbor half a dozen different species 

 of Taenia, though Leidy has observed but one in 

 our domestic fowl, and this but rarely. In the 

 turkey, guinea-fowl, and pea-fowl, no species has 

 been observed. In the sage-fowl (Centrocercus 

 urophasianus), tape-worms are often found in 

 large numbers, sometimes so as to distend the in- 

 testines : the species seems to be Taenia microps 

 Diesing. The i-eed-bird or rice bird (Dolichonyx 

 oryzivorous) is also infested with tape-worms 

 (Taenia pestifeia). Leidy has found that in a 

 bunch of a dozen obtained in the Philadelphia 

 market three or four individuals will contain this 

 parasite. The thin birds are the ones especially 

 affected, the fat ones being commonly exempt. 

 Tape-worms have also been found in the yellow- 

 breasted chat (Icteria virens), the cow-bird (Molo- 

 thrus ater), the quail (Ortyx virginianus), the 

 chuck-wills-widow (Antrostomus carolinensis), the 

 blue heron (Florida coerulea), the robin (Turdus 

 migratorius), the woodcock (Philohela minor), 

 and in the horned grebe (Podiceps cornutus). 



— Dr. Wilcox of Washington, D.C., writes to 

 the Medical record that the cow-boys of Idaho 

 treat animals affected with ' loco ' poisoning, to 

 which he has already referred in Science, by am- 

 putating the tails of the affected animals. The 

 paralysis is due to congestion of the spinal cord, 

 the posterior parts of the body being first affected. 

 The plants which are charged with producing this 

 poisoning are Oxytropis Lambertii, Astragalus mol- 

 lirimus, and possibly others of the leguminosae. 

 The cow-boys call these plants 'lark spur,' although 

 true larkspur is not found in their line of march, 

 •nor at the season when loco-poisoning occurs. 



