220 NATURAL SCIENCE. Sept.. 



probable history of sexual and asexual reproduction in plants, Pro- 

 fessor Strasburger went on to speak of plants which exhibit alterna- 

 tion of generations. In these forms it is invariably found that in the 

 nuclei of the germ-cells of the asexually produced individuals, a 

 definite number of chromosomes is always present when the nucleus 

 is in an active stage. This number appears, at any rate in the case 

 of the lower cryptogams, to be twelve. Hence it follows that a 

 fertilised ovum contains twenty-four. This latter number charac- 

 terises every cell in the body of the sexually produced individual up to 

 a certain point, i.e., the appearance of the egg or spore mother-cells. 

 At this point a reducing division sets in, and the number of chromo- 

 somes in every spore formed is lessened to half its original number 

 i.e., twelve. 



The exact nature of this reducing division is not yet evident. 



Carrying these observations further, he finds that in the higher 

 phanerogams, where the sexual generation may be suppressed, the 

 same sudden reduction from sixteen to eight chromosomes occurs 

 previously to the formation of the germ-cells. From these facts he 

 concludes that the reducing division in these plants marks phylo- 

 genetically a more 'primitive condition in which alternation of genera- 

 tions obtained. Professor Bower is translating Professor Strasburger's 

 paper, and the full text of the translation will appear in a forthcoming 

 number of the Annals of Botany. 



Physiology. 



Professor E. A. Schaefer's presidential address derived additional 

 interest from the circumstance that this is the first year since 1847 

 that there has been a separate section for physiology. While pointing 

 out that the enormous increase in England of those devoting them- 

 selves to physiology as a special science had led to the reappearance 

 of this as a separate section of the Association, Dr. Schaefer suggested 

 that it might not be advantageous to have one at every meeting of 

 the Association. " Physiology is, above all things, a practical 

 science. It requires laboratories and means of demonstration. 

 Physiologists are rarely satisfied with the opportunity of hearing and 

 reading papers ; but require that, as much as possible, the actual 

 methods of research employed should be capable of demonstration. 

 By this I am not to be supposed to advocate the demonstration of 

 experiments upon animals, for there are very many subjects in 

 physiology which can be both worked at and illustrated in a manner 

 involving in no sense whatever the word vivisection." 



We differ from Professor Schaefer's conclusion. To very few of 

 the sections would his words about " practical science " and so forth 

 not be applicable, and for the purposes of demonstration and explana- 

 tion of the methods of research, there are special gatherings of 

 specialists. In the case of physiology, there is that very energetic 

 Physiological Society, to which Professor Schaefer referred, and 



