Bibliographical Notices. 205 



animals resemble them most, and indeed, at present, are not distin- 

 guishable by any acute characters. 



16. We conclude also that the germs of Vaucheria and the allied 

 Algae are animal embryos which cannot raise themselves above this 

 embryonic condition, and after a short existence resume the vege- 

 table nature to which they owed their origin. 



Note. — In the number of* Annales des Sciences Naturelles ' for May 18 13, 

 M. Thuret has pubhshed an interesting memoir on the movement of the 

 spores of Alg«, and has gone over the same ground with Unger, arriving 

 at similar results. He is convinced that a great number of reputed species 

 of Vaucheria are mere varieties. There is, however, a portion of his memoir, 

 on a point simply indicated by Unger, which demands the greatest attention, 

 viz. tliat relative to the motion and structure of tlie graiudes contained in the 

 articulations of ConfcrvcB, Clicctophora, &c. In Conferva and Chcelophora he 

 finds the granules furnished at the narrower end witli two, or at most three, 

 flageUiform, extremely slender appendages, on which their motion appears to 

 depend, while m Prolifera (= VesictiUfera, Hassall) there is a circle of ap- 

 pendages. The granules of Conferva differ therefore very little from the 

 grtumles of the red snow, which, if M. Thuret's observations be confirmed, 

 may after all be a vegetable. At least, if it be not so considered, it will be 

 very difficult to deny the animality of the spores of Conferva. 



Recherches sur la Rube/action des Eaux et leur Oxygenation par les 



Animalcules et les Algues. Par Aug. et Ch. Mon-en : Bruxelles, 



4to, pp.130, pi. 7. 



This M'ork, which has been kindly communicated by the authors, 

 consists of a series of memoirs, of which the first relates to the oxy- 

 genation of water by means of Algas and Infusoria, and the remainder 

 to its rubefaction and the description of various species by which the 

 change in colour is effected. It is the result of observations made 

 by two relations, Augustus and Charles Morren, of whom the former 

 is Proviseur of the Royal College of Angers and a celebrated che- 

 mist, the latter Professor of Botany in the University of Lifege and 

 an accomplished zoologist. 



There is a singular difference in the quantity of air which exists 

 at different times in running and stagnant water, as also in the quan- 

 tity of oxygen comprised in this air at different hours of the day. The 

 proportion of oxygen varies from 25 to 48 or 61 per cent, from sun- 

 rise to 5 o'clock in the afternoon. The subject is obviously of great 

 importance as regards health and in many other points of view, 

 and it is to the consideration of it that the authors have applied 

 themselves in the first memoir. The cause of these differences is 

 found in the influence of light on the respiration of the Infusoria and 

 Algse which are contained in the water. 



The influence of oxygen is very great on the salutary quality of 

 this universal beverage ; on the degree of its action on the nutrition 

 of vegetables, and conser^uently when used for irrigation ; nor is it 

 less active as regards the art of bleaching and dyeing. It is easy, 

 from what has been said, to perceive the great importance of the 

 subject, and it is difficult to imagine to what results it may finally 

 lead. In a philosophical point of view we may remark, that it ex- 



