AppxIL 13, 1888.] 



SCIENCE. 



iSr 



The things saved out were used by the children for two or three 

 days. The rest of the rubbish was burned. Near the last of 

 December the three children were taken sick with scarlet-fever." 



The diagram (A) exhibits in a condensed form the experiences of 

 the health-officers in Michigan relating to scarlet-fever during the 

 year 1886. It shows, that, in the 324 outbreaks, the average num- 

 ber of cases was 5.30, and the deaths were .31 ; that in the 45 out- 

 breaks in which isolation or disinfection, or both, were neglected, 

 the average number of cases was 13.84, and the deaths 1.02 ; that 

 in the 58 outbreaks in which isolation and disinfection were both 

 enforced, the average number of cases was only 2.74, and the aver- 

 age number of deaths .19, the difference being an average of 11. 10, 

 and .83 deaths, indicating a saving in these 58 outbreaks of 644 

 cases and 48 deaths. This saving is shown not simply by com- 

 parison with those outbreaks in which nothing was done, but also 

 with outbreaks in which either isolation or disinfection was en- 

 forced. 



A table (compiled in the office of the secretary of the State board 

 of health, from reports made by local health-officers) giving the 

 basis for the diagram and foregoing statement is as follows : — 



Scarlet-Fever in Michigan in 1886. 



(0 



All Outbreaks. 



(=) 

 Isolation or Disin- 

 fection not men- 

 tioned, or 

 Statements Doubt- 



Isolation or Disin- 

 fection, or Both, 

 Ne,;lected. 



^4) 



Isolation and 



Di.infection 



Both Enforced. 



(324 Outbreaks.) 



ful. 

 (220 Outbreaks.) 



(45 Outbreaks.) 



(59 Outbreaks.) 



Totals.... 



Cases. 

 1,7.6 

 5-30 



Deaths. 

 0.3T 



Cases. 

 914 



Deaths. 

 41 



Cases. 

 623 



Deaths. 

 46 



Cases. 

 .9 



Deaths. 

 13 



Averages. 



4-15 



0.19 13. 84 



1.02 1 3.03 



0.22 



BOOK-REVIEWS. 



Geology. Chemical, Physical, and Stratigraphical. Vol. II. By 

 Joseph Prestwich. Oxford, Clarendon Pr. 8°. 



The present volume of Prestwich's ' Geology ' treats of stratig- 

 raphy and physical geology, — the history of the earth as traced from 

 the study of strata and fossils. In the first volume of this great 

 work, which appeared in 1SS6, the composition of rocks, and the 

 changes brought about in them by the various meteorological agen- 

 cies on the surface, and by thermal and chemical action at depths, 

 were discussed, and the nature of the disturbances which the rocks 

 have undergone by the action of subterranean agencies, the eleva- 

 tion of mountain-chains, and the manner of volcanic action, were 

 described. This discussion of dynamic geology is now followed 

 by a geological history. As the handbook is mainly intended for 

 use in Europe, the geological history of Europe, more especially 

 that of Great Britain, is treated more fully than that of other coun- 

 tries ; but the author, after having described the geological history 

 of a period in Great Britain, gives a sketch of the contemporaneous 

 course of events in other parts of the world. 



The volume deals naturally with two classes of geological data, 

 — paleontological and physiographical. The description of the 

 evolution of life in the various periods and areas is profusely illus- 

 trated by carefully selected illustrations, part of which are printed 

 in the text, while others are shown on lithographed plates. The 

 cuts show the characteristic classes and orders which are peculiar 

 to the greater divisions, while the plates show characteristic genera 

 of each group. In discussing the lesser divisions of formations, 

 figures representing important species are inserted in the text. By 

 this arrangement of illustrations, and by a careful choice of the best 

 among the available material, the author has succeeded in making 

 the volume very instructive and useful to the student. He dwells at 

 some length on the results of recent discoveries, and on the im- 

 portant part played by sponges and foraminifera in building up cer- 

 tain sedimentary strata. The relation of the globigerina ooze of 

 the deep seas to the chalk is fully discussed ; and the author shows 



that the physical conditions of the deep sea of the present time, 

 with its cold polar water, and those of the cretaceous sea, which 

 was probably not so deep, and certainly not so cold, were so differ- 

 ent that their deposits must necessarily be different. He compares 

 the chemical and physical composition of the chalks to that of the 

 globigerina ooze, and shows that the former is far purer than the 

 latter, and that no equivalent deposit is forming at the present time. 

 " The conditions under which it was deposited were peculiar and 

 special ; and, though it presents many points of analogy to the cal- 

 careous ooze, there are none of identity ; and the chalk stands alone 

 among the British strata in its peculiar structure and origin. It is 

 for these reasons that I have taken the opportunity of making the 

 foregoing remarks, not because the chalk forms an exception to 

 the general rule of constant change, but because its features are so 

 clear and so well marked that it serves better than most other de- 

 posits to illustrate this law of unceasing variation." 



The range of genera and species of the same period through 

 space is also briefly described. The geophysical problems which 

 geological history has to treat are wisely confined to the concluding 

 chapters, where the student will find the most important theories 

 held by physicists discussed, so far as they can be proved or refuted 

 by geological data. The author himself advocates the theory of a 

 thin crust, a solid nucleus, and a viscous magma between the two, as 

 he believes that the motions of the earth's crust can only be ex- 

 plained by such a theory. 



The volume has a very full index, and is accompanied by a geo- 

 logical map of Europe compiled by William Topley and T. G. Good- 

 child. The colors adopted resemble, for the most part, those pro- 

 posed by the International Geological Congress, with the exception 

 of the Trias, Permian, and Siluro-Cambrian, for which the tints 

 more familiar to English geologists were retained. 



NOTES AND NEWS. 



About one hundred and fifty scientific men and women of Wash- 

 ington gathered in the hall of the Columbian University on the even- 

 ing of Thursday, April 5, to pay their tributes to the memory of Dr. 

 Asa Gray, the eminent botanist, and to listen to addresses by sev- 

 eral of his intimate friends and co-workers. The president of the 

 meeting was Professor Langley, secretary of the Smithsonian Insti- 

 tution, who opened the exercises with a brief tribute to the memory 

 of Dr. Gray. Professor Chickering delivered the first address, giv- 

 ing a sketch of the life and life-work of Dr. Gray, tracing the grad- 

 ual unfolding from the pioneer's life of boyhood to the finished 

 scholar and true scientist of middle and later life. The world is 

 indebted to him, he said, for popularizing botany. He put into 

 plain English that which interested people. He had a genius for 

 work. Work was a delight. He was never in a hurry. He had 

 time for social enjoyment with his friends, as well as for investiga- 

 tion and the preparation of a great number of books. He conducted 

 a very large correspondence, but he economized time and labor 

 even in this. He often returned a letter containing a great number 

 of questions with simply 'yes' or ' no ' written at the bottom of 

 each. Professor Chickering also spoke of the honors that had been 

 heaped upon him. He was a member of the Royal Society of Lon- 

 don, and, of the Institute of France, one of the eight immortal 

 foreign members. Professor Chickering spoke of the last year of 

 his life as the happiest, and closed with an eloquent tribute to his 

 memory. Dr. Vasey of the Agricultural Department spoke of the 

 influence Dr. Gray exerted upon botanical science. He began 

 with a review of the state of botanical knowledge before his time, 

 spoke of his studies under Dr. Torrey in New York, of his botanical 

 text-books, and of his investigations of the collections made by the 

 government and by private individuals. He spoke in detail of his 

 work; said that during his lifetime the number of known botanical 

 species upon the continent of North America had increased from 

 4,o8r to more than 11,000, and the numberof volumes of his school- 

 books published was more than half a million. Prof. L. F. Ward 

 of the National Museum spoke of Dr. Gray's relations to the dis- 

 covery of the theory of evolution, showing that Mr. Darwin had the 

 greatest confidence in him, and intrusted to him, almost before he 

 did to any other, the secret of his great discovery. Dr. Gray was 

 one of the first to understand and appreciate the importance of Mr. 

 Darwin's work, and did more than any other to make it acceptable 



