144 



SCIENCE. 



[Vol. IV., No. 81. 



sible to retain these orders any longer. Stoliczka 

 came to this view long ago, and much corroborative 

 evidence has come to hand since. In fact, there does 

 not at present seem to be any good basis for ordinal 

 divisions in the Lipocephala. The divisions adopted 

 by Professor Lankester are not unnatural; but they 

 appear to have merely an approximate value, and 

 shade into one another to such an extent as to be of 

 little systematic use. 



(6) There is nothing to prevent any such concep- 

 tion; but, unfortunately, there is no evidence, as yet, 

 that it would conform to any subjective reality. A 

 parallel statement would be, that the wool on a ewe 

 ' replaces ' the horns on a ram. We can conceive 

 that woolly or hairy secretions may be so modified as 

 to produce horns, and, in fact, do produce them oc- 

 casionally. The importance of the shell-gland in the 

 embryonic condition of the Mollusca, as shown by 

 Trofessor Lankester, than whom none have con- 

 tributed more valuable investigations on this topic, 

 forbids that we should consider these secondary cu- 

 ticular products as its equivalent. That they are 

 nothing less than identical with Chiton spines will, I 

 think, be admitted by any. one who compares the 

 figures of Keincke and Hubrecht on Chitons and Neo- 

 menia respectively. There are also a great variety of 

 other Chiton spines; and on some Fissurellidae, and 

 even in some brachiopods, analogous structures may 

 be found. 



In conclusion, Mr. Editor, permit me to express 

 the hope that these more or less unimportant defects 

 in detail, which are inevitable to all work of a general 

 character, may not obscure what I have endeavored 

 to state clearly (namely, the great value and useful- 

 ness of Professor Lankester's work), nor delay what I 

 believe will be its eventual consequence, — an im- 

 portant reformation in our general molluscan systems. 



W. H. Dali, 



The earthquake of Aug. 10. 



It is a little remarkable that the earthquake-shock 

 of yesterday should have been felt with considerable 

 force in the city of New Haven, which is built upon 

 a sandy plain, while it was perceptible only as a short 

 series of lateral vibrations, lasting about a second and 

 a half, and so slight that it was unnoticed by most 

 persons in the vicinity of the observatory. The 

 observatory is built on a sandstone ledge, and is 

 about a hundred and fifty feet above tide-water, in 

 (geodetic) longitude west 72° 55' 19.15", and latitude 

 north 41° 19' 28.48". 



At the time of the vibration the writer was sitting 

 at a table, and its probable origin at once occurred 

 to him. Allowing for the few seconds occupied in 

 taking out his watch, the tremor occurred at 2 h. 7 m. 

 25 s. ; and, as the watch at tbat time was 1.5 s. slow of 

 the fifth hour west from Greenwich local mean time, 

 the tremor may be set down as beginning at 2 h. 7 m. 

 27 s. by this mean time; and I should estimate the 

 uncertainty at not more than 2 s. 



Leonard Waldo. 



Yale college observatory, Aug 13. 



On Sunday, Aug. 10, at 2h. 8 m., I felt an earth- 

 quake, lasting three or four seconds. The oscillatory 

 movement was from a little south of west, toward a 

 little north of east. The oscillations were rapid but 

 slight, with maximum intensity between the first 

 and second second, when the movement began grad- 

 ually to decrease. The accompanying sound was like 

 the rumble of artillery-wagons. Jules Marcou. 

 Cambridge, Aug. 10. 



EPIDEMIC CHOLERA AND INFECTIOUS 

 DISEASES. 



The presence of cholera this summer in 

 epidemic form in southern France, the appear- 

 ance of sporadic cases at widely scattered 

 places and on shipboard at various seaports 

 of the European continent and of England, 

 have brought western civilization once more 

 face to face with two of the most important 

 problems which modern science and social 

 organization can be called upon to solve. 

 These problems just now come home to every 

 one, but in ordinary years are put out of mind, 

 or left to the care of laboratoiy devotees, or of 

 officials charged with departments concerned 

 with public fiygiene. 



The first involves a purely scientific ques- 

 tion as to the causes, modes of origin, and 

 ways of propagation, of the infections or so- 

 called zymotic diseases : the second, evolving 

 itself naturally from the first, is of a more 

 immediatel}' practical nature, and deals with 

 the processes best calculated to prevent and 

 antagonize these diseases, especially when 

 presenting themselves as epidemics. And 

 these problems owe this much to such epidem- 

 ics, — that by them men as individuals, and 

 governments (their representatives) , are stim- 

 ulated to a vigor of inquiry and action which 

 are never evoked by a customary rate of mor- 

 tality, however high, from endemic diseases, 

 such as are always with us ; just as the stim- 

 ulus of prospective want often meets with 

 a ready response where chronic destitution 

 makes an ineffectual appeal to action. T} T - 

 phoid- fever, resembling cholera ve^ much in 

 its propagation, demands a steady toll from 

 the populations of Europe and North America, 

 compared to which the occasional ravages of 

 cholera become insignificant ; and } 7 et it is 

 impossible to inspire them with an intelligent 

 dread of that enemy expressing itself in pos- 

 sible and comparative^ simple precautions. 

 The self-reliant Anglo-Saxon continues to re- 

 gard typhoid-fever with a measure of the same 

 indifference felt bj T the fatalist of India toward 

 cholera; and the explanation is to be found, 



