292 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



ployed with success consists in the use of a concentrated so- 

 lution of picric acid. He preserved in this way, for about six 

 weeks, some small medusa?, and, on exhibiting them to the 

 Academy, they presented all the clearness of their forms, and, 

 to a great degree, all their tissues. The only change was in 

 certain smaller medusae, which became slightly opaque. The 

 JVoctilucce he was able to study, thus prepared, as well as 

 though living before him. Bulletin Acad. Boy ale des Sci- 

 ences deBelgique, 1871, 179. 



NEW EDITION OF DARW t IN's " ORIGIN OF SPECIES." 



Some idea of the amount of interest experienced in regard 

 to the views of Mr. Darwin upon the genesis of species may 

 be gathered from the fact of the recent publication, by Mur- 

 ray, of the sixth edition of the work entitled " The Origin of 

 Species by Means of Natural Selection." Numerous correc- 

 tions and additions have been made to the work as it was 

 previously known ; and with his usual candor, Mr. Darwin 

 has made use of the numerous criticisms of his works that 

 have appeared, and has allowed them to modify materially 

 his opinions in certain directions. As might have been ex- 

 pected, much of the new matter is devoted to answering the 

 objections of Mr. Mivart, perhaps the most able of his antag- 

 onists. Mr. Bennett, in his notes on the work, thinks that 

 each successive edition of the " Origin of Species" lessens the 

 distance between Mr. Darwin and those who believe that the 

 influence of natural selection, though a vera causcc,have been 

 overrated as an element in the evolution of species. 



If it is admitted that important modifications are due to 

 " spontaneous variability," that natural selection is not the 

 exclusive means of modification, Darwinians and non-Dar- 

 winians have equally before them the problem to discover 

 what these other laws are which are co-efficient in the pro- 

 duction of new species, and what part each of these plays in 

 producing the final result. 12 A, Feb. 22, 1872, 316. 



MICROSCOPIC FORMS IN CHICAGO WATEB. 



Mr. Babcock, of Chicago, has contributed an interesting 

 article to the "Lens" upon the effect on the hydrant water 

 of the reversal of the current of the Chicago River. It is 

 well known that during the past year an engineering enter- 



