208 SUMMARY OF CURRENT RESEARCHES RELATING TO 



SUMMAEY 



OF CUEEENT RESEAECHES EELATING TO 



ZOOLOaY AND BOTANY 



(principally Invertebrata and Gryptogamia), 



MICROSCOPY, &c., 



INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.' 



ZOOLOGY. 



A. VERTEBRAT A :— Embryology, Histology, and General. 



a. Embryology- 1 

 Special Physiology of the Embryo. — Prof, W. Prayer's | most 

 important general results on this subject are that mobility appears 

 long before sensibility, and that the sense-organs and the parts of the 

 nervous system connected with them are capable of functioning before 

 it is at all likely that in normal embryonic life they have any proper 

 functions to perform. By "mobility" is to be understood more 

 especially the power of making spontaneous or " impulsive " move- 

 ments. The presence of sensibility can only be proved by the exist- 

 ence of what is really a kind of mobility — that is, reflex mobility. 

 When the appropriate reflex movements are obtained on stimulating 

 the sense-organs, it is inferred that the corresponding kind of 

 sensibility is present. Keflex movements are not only later in 

 appearing, but can also be made to disappear more easily than 

 impulsive movements. The movements that indicate sensibility can 

 be suppressed (in the artificially extracted embryo of the rabbit) by 

 applying chloroform to the skin; with more difficulty by causing 

 chloroform to be breathed. In either case the anaesthesia passes 

 off very rapidly. It is supposed that the chloroform in the first 

 case acts directly, in the second case indirectly, on the nerves of 

 the skin ; that it only secondarily affects the spinal cord, and that it 

 does not act at all on the brain. The movement of sensibility in the 

 embryo gradually rises from its first appearance up to birth. In the 

 embryo of the rabbit, the skin being irritated, two seconds may pass 



* The Society are not intended to be denoted by the editorial " we," and they 

 do not hold themselves responsible for the views of the authors of the papers 

 noted, nor for any claim to novelty or otherwise made by them. The object of 

 this part of the Journal is to present a summary of the papers as actually published, 

 and to describe and illustrate Instruments, Apparatus, &c., which are either new 

 or have not been previously described in this country. 



t This section includes not only papers relating to Embryology properly so 

 called, but also those dealing with processes of Evolution, Development, and 

 Keproduction, and with allied subjects. 



\ xii. and 644 pp., 8vo, Leipzig, 1885. 



