Ixxxii GENERAL SUMMARY OF SCIENTIFIC AND 



ZOOLOGY. 



The year lias been characterized by the appearance of 

 several works of great importance that tend to revolutionize, 

 in a degree, the science oi Zoology^ and that evidence the flow 

 of a counter-current in the ordinary channels of zoological 

 thought. Much of this tendency is undoubtedly due to the 

 influence of Darwin's writings, and much to improved meth- 

 ods of research in studying the tissues of animals, and in cut- 

 ting and staining sections of the soft-bodied creatures, such 

 as worms, and the eggs of the lower animals, as well as the 

 embryos of the vertebrate animals. 



The influence of Mr. Darwin's work is noticeable in the en- 

 tirely new path by which naturalists approach the study of 

 the instinct or mental nature of animals. The key-note to 

 th subject is that the instincts of animals are the result or 

 sum of inherited habits ; ^. e., that the present mental or in- 

 stinctive processes of animals are the result of a slow growth, 

 through many generations, of what were originally quite sim- 

 ple mental acts. More is, perhaps, being done in the way of 

 observation and experiment than ever before, and we would 

 refer the reader to numerous articles in Nature^ by Mr. Dar- 

 win, Mr. Spalding, and others, on this interesting subject. 



In the physiology of the lower animals, the brilliant re- 

 searches of Professor A. M. Mayer on the sense of hearing in 

 insects will receive much attention, while the studies of M. 

 Simon on the blind insects inhabiting European caves bears 

 on the subject of the sense of sight. M. G. Pouchet concludes 

 from his experiments on the influence of light on certain dip- 

 terous larva) wanting external organs of sight, that dipter- 

 ous larvfe generally perceive not only light, but also appre- 

 ciate the direction whence the light comes. 



The anatomy of the brains of certain quadrupeds has been 

 studied by Professor B. G. Wilder, while the physiology or 

 topography of the diff*erent mental traits in man has received 

 attention from Fritsch, Hitzig, Jackson, and Ferrier ; and 

 from their researches some are led to think that we may ulti- 

 mately be able to assign the various mental faculties to defl- 

 nite portions of the brain. 



The vexed question of spontaneous generation has, since 

 the appearance of Bastian's " Beginnings of Life," been suf- 



