270 Chronicles of Science. [April, 



is rolled up like that of the ferns. The motion of the spermatozoid 

 consists chiefly of a rotation round its own axis, by which it wriggles as 

 it were through the water bearing the cilia in front. The duration of 

 the motion varies from a few minutes to many hours. Spermatozoids 

 may be preserved for microscopical purposes in a solution of tannin 

 (10 grains to the ounce), and in a solution of corrosive-sublimate 

 (1 grain to the ounce) or in glycerine. The cilia are best seen after 

 the spermatozoids have been slowly dried on the object-slide. 



M. Corenwinder, in a communication to the Academy of Sciences, 

 Paris, details experiments which lead him to the conclusion that 

 neither the flowers nor the leaves of plants exhale carbonic oxide, or 

 other combustible gases. He found that leaves exposed to the sun 

 with a notable quantity of carbonic acid present, absorbed C0 2 rapidly 

 but did not exhale CO. 



The able Horticulturist Knight stated, that according to his obser- 

 vations a high temperature favoured the production of male flowers, 

 while a lower temperature gave origin to female blossoms. He 

 accounted in this way for the sterility of many plants grown in high 

 temperatures. Naudin, however, is not disposed to adopt this view. 

 He has made observations for ten years at least, on Cucurbitaceae, and 

 he finds that the male and female flowers appear to be independent of 

 the state of the temperature. The character of the blossoms of these 

 plants is according to him intimately connected with peculiarities of 

 temperament which vary in different species and races, and even 

 among individuals of the same race. The races of melons, squashes, 

 and gourds, which have been long cultivated in Northern Europe, are 

 comparatively more precocious and vigorous under heat for ripening 

 their fruit than those of the same species recently introduced from 

 tropical countries. Cucurbitacese attain their period of flowering and 

 fruiting sooner under the hot and cloudless sun of the South of France 

 than in Paris, where they grow luxuriantly, but do not flower well. 



Mohl has examined the flowers of Oxalis, Viola, Specularia, and 

 Impatiens, and has shown that self-fertilization must occur in these 

 cases. In these plants the small and closed flowers are the fertile 

 ones. In them the anthers while smaller in number have more 

 active pollen. In Oxalis Acetosella, for instance, the larger anthers 

 of the closed flowers contain only about 2 dozen pollen grains, 

 and the smaller scarcely a dozen ; while in the normal flowers the 

 pollen grains are very numerous. The tubes from the pollen in the 

 closed flowers send out their tubes to seek the stigmas, even at a con- 

 siderable distance. From his researches, Mohl concludes that it is 

 not a general law in hermaphrodite flowers, that nature should permit 

 fecundation by the pollen of another flower in preference to its own 

 pollen. In Fumariacea? he remarks that the transport of pollen from 

 one flower to the stigma of another is impossible on account of the 

 mode in which the anther and stigma are enclosed by the petals. 



Professor Lawson refers to a very remarkable boulder, in the Trent 

 Valley, in Upper Canada, which was visited by him in company with 



