200 THE AMERICAN MONTHLY [June 



which had been sug'g'ested to him l)y the presence of B. 

 eoli in tlio blatlder. On these media the microbes grew 

 luxuriantly, forming- g-reyish colonies; the B. typhi abd. 

 less rapidly in fine transparent patches. In the discussion 

 Eisner said there were plenty of differential sig-ns ; the 

 difficulty was to cultivate Eberth's bacillus when it was 

 only present in small numbers — for instance, in water, or 

 mixed with other bacteria, for example, in stools. Evvald, 

 Wolf, and Senator, all had found Eisner's method very 

 useful for the diagnosis of doubtful cases from the stools. — 

 Brit. Med. Journal. 



BIOLOGICAL NOTKS. 



Fertilization of the Gymnosperms. — A very important 

 discovery in the mode of impregnation in Gymnosperms 

 made by two Japanese botanists. Professor S. Ikeno and 

 Dr. S. Hirase, which was recentl}' referred to in our pages, 

 supplies a most interesting link between this section of 

 Phanerogams and the higher Cryptogams. Dr. Hirase 

 has discovered that in Ginkgo bilaba, Salisburia adianti- 

 folia, impregnation is effected by antherozoids formed 

 within the pollen-tube. The two nuclei resulting from 

 the final division of the generative nucleus of the pollen- 

 tube are converted, before entering the oosphere, into 

 motile antherozoids, resembling those of the higher Cr3'p- 

 togams, but differing somewhat in form. They are ellip- 

 soidal 82 microns long by 49 microns broad, and contain 

 in the centre a nucleus entirely surrounded by cyptoplasm. 

 The main body consists of a head composed of three spi- 

 ral coils, and a slender tail; to the former are attached 

 numerous cilia. As soon as the anthci'ozoids Iiave escaped 

 through the apex of the pollen tube, they enter the oosphere 

 with a rapid twisting motion. Attraction spheres were 

 observed accompanying the final division of the pollen-tube 

 nucleus. Professor Ikeno has made a similar observation 

 respecting the mode of impregnation in another (iymno- 

 sperm, Cvcas revoluta. The antherozoids are here some- 

 what larger than in (iinkgo ; tile main body is composed 



