BOTANY. 121 



become a i>rotective factor to plants i^towii in t ln' dpcii, their teiH])enitiire Ixmiij; kept 

 within I'easonable ])Oun(ls in this way. 



The influence of metallic poisons on respiration, E. B. Copelaxd (,I//.s. in 

 Science, n. ser., 15 {190^), No. 377, p. 4-}4)- — Experiments are reported with Elodea, 

 Callitriehe, a crucifer, fish, and frog larvae, in whii'h copper, zinc, cadniinm, silver, 

 and mercury were used as stinnilants. It was shown that the respiration may be 

 stinnilated by a small fraction of a fatal concentration of these metals. With increas- 

 ing con<'entration the evolution of carbon dioxid becomes accelerated, sometimes 

 reaching 2o times that of the normal. The evolution of carbon dioxid continues 

 undiminished after plasmolysis is suspended by the poison. It was found that cop- 

 j>er and zinc may cause a considerable evolution of carbon dioxid from specimens of 

 Elodea that have been boiled. 



Cyanogenesis in plants, W. R. Dunstan and T. A. Henry {I'roc. Roy. Soc. 

 {London'], 70 {1902), Xo. 461, pp. 153, 154).—T\\Q authors have investigated the 

 nature of the poison contained in young jilants of tSorgJium rnhjorc. This plant, 

 under the name of guinea corn, durra, etc., is extensively cultivated in tropical coun- 

 tries as a food grain. The \oung plants have in a number of instances, especially in 

 Egypt, proved fatal to animals, and the authors show that when crushed with water 

 the young plant produces prussic acid. The acid does not appear to exist in a 

 free state, but is produced by the action of the hydrolytic enzym, which is appar- 

 ently identical with the emulsin of bitter almonds, on a cyanogenetic glucosid, 

 which has ])een named dhurrin. Dhurrin is said to differ from the amygdalin of 

 bitter almonds and the lotusin of Loins arabims in being derived from dextrose and 

 not from maltose. The poisonous properties of young plants do not seem to be in 

 any way jiresent in the seeds or older plants. The authors intend to make an 

 investigation of the general problems raised by the occurrence of cyanogenetic glu- 

 cosids in plants. 



A preliminary study of the germination of the spores of Agaricus campes- 

 tris and other Basidiomycetous fungi, Margaret C Fergusox ( T. ,S'. Jh'pt. Aijr., 

 Burcou of Plant Lndustry Bill, pj, pp. 4S, jils. 3).^K report is given of preliminary 

 studies on the germination of the spores of Basidiomycetous fungi, the principal 

 species used being Agaricus campestris. The methods of investigation are described 

 and experimental results given in detail. The effect of various agents on germina- 

 tion is shown, and the author reports having found that the germination of spores of 

 Acjaricns c<irnjies(n.'^ is favored under cultural conditions if a few^ of the spores are 

 germinated or if a small portion of the mycelium of the fungus be introduced into 

 the culture. The growth resulting in either case will cause the germination of nearly 

 all the spores in the culture, provided the conditions are such as not to be detrimental 

 to it. A historical resume is given of investigations along the same line, and a 1)rief 

 bibliography completes the report. 



Cell nuclei in some cases of parasitism or intercellular symbiosis, R. 

 Chodat {Extr. from Compt. Rend. Coiitj. Lnternat. Bol. Paris, 1900, pj). 10). — The con- 

 stant presence of many parasites, especially in some of the higher plants, has been 

 taken to be a form of symbiosis and not as jiarasitism. The author has made a study 

 of the apparent association between fungi and a number of plants to determine the 

 effect of tlie presence of the organism on the cell and particularly upon the nucleus. 

 In his studies he found that the parasite of LPippophacs rhamnoides acts towai'd that 

 plant in a similar manner as does the organism causing the club root of cabbage. It 

 is a true parasite and destroys the nucleus of the cell. In turn the parasite may be 

 absorbed by the host i>lant. The fungus parasite occurring as mycorrhiza in certain 

 orchids in the beginning acts as a true parasite, but never to the destruction of the cell 

 nucleus. After having passed a certain stage the plant seems to be able to restore 

 the attacked cells and no permanent injury is inflicted. In the case of leguminous 

 plants the bacterial parasite seems to ])e present in a true symbiosis, the host toler- 



