BOTANY. 



New Studies in Fecundation. — M. Leon Guignard publishes 

 a paper in the 1 Annates des Sciences Naturelles, entitled " Now Studies 

 of Fecundation, with a comparison of the morphological phenomena 

 observed in plants and in animals." 



He reminds us that until very recently the essence of fecundation 

 was supposed to reside exclusively in the union of two nuclei of 

 different sexual origin, and that the protoplasm played but an acces- 

 sory part in the process ; that in phenogamous plants, for instance, the 

 male nucleus penetrates alone the oosphere to the exclusion "i & 

 accompanying protoplasm. His recent observations, however, and the 

 discovery of certain new bodies, new at least in vegetable cells, which 

 he calls "directive spheres" and which play their part in the process 

 throw quite anew light upon the subject and moreover bring into 

 close accord the phenomena as existing in the two kingdoms. He 

 follows the development of the reproductive elements, male and 

 female, from the very beginning to their adult stage >o as to determine 

 the mode of differentiation by which they acquire sexual characters 

 and then further follows these sexual elements, showing which are 

 the essentially active parts, and how the union between them takes 

 place to form the first embryonic cell. 



The account which he gives of the technique employed in his 

 researches is far from satisfactory; indeed he says himself that the 

 " technique applicable to the study of vegetable protoplasm leaves 

 much to be desired." As fixative agents he used absolute alcohol, 

 corrosive sublimate, picric acid and osmic acid ; to stain the proto- 

 plasm and the spheres he hardened the specimen in absolute alcohol 

 and then in 10 per cent, solution of zinc sulphate or ammonia alum, 

 followed by hsematoxylin. Fuchsine and methyl green proved also of 

 special value in distinguishing the plasmic contents of the cells. 



He first describes the formation of the reproductive cells, the pollen 

 grains and the embryo sac, using as his subject a specie- of bty 

 Li li ii,i> martagon. He traces each step in clear language and by the 

 aid of beautiful figures, from the undiflferentiated meristem of the 

 budding anther to the archesporia or pollen mother-cells, to the 

 special mother-cells and the mature pollen grains: and with the same 

 nicety, the origin of the embryo sac with the egg apparatus (oosphere 



'Ann. Sci. Nat.; Bot. Tome XIV. pp. 163-288. Plates 9 to 18. 



