BOTANY. • 393 



extent Lactuca saligna, Aplopappus rtihiginosiis, CliondriUa jiincea, and 

 probably other plants, also place their leaves in a meridional position. 

 The cause of this he attributes to the unusually great sensitiveness of 

 the leaves of the species named to the action of light. 



The subject of i)lant respiration hds been studied by Borodin, who 

 maiutains more strongly than ever his opinion that the energy of the 

 respiration in leafy shoots under constant external conditions is a func- 

 tion of the carbohydrous material which is present in the plant. Dr. 

 Th. W. Engelmann, in a paper in the Botauische Zeitung, describes a 

 new melhod for the investigation of the exlyilation of oxygen by plants 

 and animals. He makes use of the bacteria, which commonly produce 

 putrefaction. Their motions cease when the supply of oxygen is shut 

 off, and revive when it is renewed, and by watching their motions one 

 can tell whether oxygen is being evolved by plants or animals near 

 them. 



In the Botanische Zeitung for 1880, Schimper gave an account of the 

 origin of starch-grains, and this was followed in 1881 by a paper on 

 GroictU of Starch grains, in which the author expresses the view that 

 starch-grains are crystalloid substances, and he opposes strongly the 

 view of Naegeli that they increase by intussusception. In reply Naegeli 

 published an article in the same journal, uiiholding his original view 

 against Schimper. Arthur Meyer, in an article which also appeared in 

 the Botanische Zeitung, -on the Structure of Starch- grains, takes the 

 ground that Naegeli's theory of intussusception has not been disproved 

 by Schimper's observations, although he agrees that Schimper's hypoth- 

 esis, that starch-grains are si)hferocrystalloids of a carbohydrate, affords 

 the simi^lest explanation of the formation of the layers. 



The crystalloids found in marine algse are described in Pringsheim's 

 Jahrbiicher by Klein. The paper is followed by one on the Crystalloids 

 in the Niiclei of Phigidcida and XJtrictdaria. Zacharias has two papers 

 in the Botanische Zeitung; one on the Chemical Constitution of the 

 Nucleus, and the other on Spermatozoids. The main part of the nucleus 

 of vegetable cells consists of nuclein, which is also found in what Stras- 

 burger calls the nuclear i)late formed during cell division. In the 

 second pa])er Zacharias states that as far as their chemical composition 

 is concerned the spiral bands of the spermatozoids of plants resemble 

 the bodies of the spermatozoa of animals, while the cilia resemble the 

 tails of the latter. Furthermore the spiral bands, as is shown by their 

 containing nuclein, originate in the nuclei of the mother cells, while the 

 cilia arise from the cell-plasma. Tae Untersuchungen of the Gottiu- 

 gen laboratory contain papers by Eeinke and Kodewald entitled Studien 

 iiber Protoplasma. The first gives detailed analyses of the protoplasm 

 of MthaUum septicum. The other papers relate more particularly to the 

 assimilation and metastasis occurring in cells. According to Prof. F. 

 Schmitz, in an article on Formation and Groicth of the Cell-membranes of 

 Plants, the cell walls are formed by centripetal apposition, and not by 



