2433 Journal of Applied Microscopy 



one of these cells being larger than an entire embryo at the ten celled stage. 

 Double fertilization was not actually observed, but there are indications that it 

 occurs. c. J. c. 



Guignard, L. La double fecondation chez les In a recent Study of Capsella Bursa- 

 Cruciferes. Jour, de Botanique, 16: 361- pastoris and Lepidium sativum Prof. 

 36s, figs. 20, 1903. -^ _ ^ 



Guignard reports " double fertilization " 



in both forms. In Capseila the fusion of the polar nuclei is very late. At the 

 time of fertilization the antipodals are much reduced and soon disappear. The 

 male cells while in the pollen tube are closely applied to each other and are 

 either ovoid or slightly elongated. A delicate faintly staining envelope of cyto- 

 plasm surrounding each nucleus could be observed with great difficulty. This 

 is extremely interesting, as it seems to show that fertilization may be not merely 

 a union of nuclei but also a fusion of cytoplasm with cytoplasm. 



In Lepidium sativutn the male cells are fully formed in the pollen grain. As 

 in Capsella, they remain close together until discharged into the embryo-sac. 

 Chicago. W. J. G. Land. 



CYTOLOGY, EMBRYOLOGY, 



AND 



MICROSCOPICAL METHODS. 



AGNES M. CLAYPOLE, Throop Polytechnic Institute. 



Separates of Papers and Books on Animal Biology should be sent for Review to Agnes M. Claypole, 



55 S. Marengo Avenue, Pasadena, Cal. 



Ancel, P. Sex Determination of Gametes in The author maintains, with especial 

 Hermaphrodite Gonads. Arch. Zool. Ex- , j.^ ,. 11 



per. ID (Notes et Revue), 84-94, 1902 (Re- reference to He/ix pomafia, that the 

 view in Journ. of Royal Micr. Soc, Feb., sex-cells are at first indifferent. That 



those which appear before the nutritive 

 elements are formed become male cells, giving origin to spermatozoa, and that 

 those which appear after the appearance of the nutritive elements become ova. 

 This conclusion the author thinks may be extended to similar cases ; the " cyto- 

 sexual " character of the gametes is thus determined by the time of their 

 appearance in relation to the appearance of the nutritive cells. (This is an inter 

 esting confirmation of the general results pointing to the greater quantity of 

 nutrition required for producing ova.) a. m. c. 



Scriven, J. B. Preparing Serial Sections of The technique of Lowne is generally 

 Insects. Journ. Quekett Micr. Club, 8 : , ,, , , , . . ,. 



343-348, 1902. (Rev. Journ. of Roy. Micr. followed, but several time-savmg modi- 

 Soc, Feb., 106, 1903.) fications are introduced. After fixa- 



tion the object is dehydrated in hot absolute alcohol and put at once into the fol- 

 lowing embedding medium: Paraffin (45° C.) 80 grs., white wax 10 grs., anhy- 

 drous creosote 2 minims, solution of caoutchouc in pure benzol (1 gr. to 5 fluid 

 drs.) 2 minims. This medium cuts well at the temperature of the room (about 

 16° C.). The sections are stretched on and fixed to the slide with warm water. 

 After drying by evaporation the embedding medium is removed by a rapid flood- 

 ing with benzoline, which in its turn is removed with absolute alcohol. Other 

 steps are those usually adopted. a. m. c. 



