ZOOLOGY. 21 



phyll c'(>ntaino(l in the Icavcj?, as well as to greatly reduce the root system. On the 

 other hand, the dry air checked the growth and development of stems and leaves, 

 increased the diameter of the stems, diminished the leaf surface, and greatly increased 

 the num1)er and distribution of the roots. In the later paper, the effect of the same 

 factors on the structure of plants was shown. Dry air increased the thickness of 

 the epidermis and the numl)er of stomata. It also increased the production of ligne- 

 ous tissue, hastened the differentiation of the sclerenchyniatous tissue and also the 

 pith. There was under the influence of the dry air a much greater development of 

 palisadi' tissue in the leaves. In the humid air these structures were less differen- 

 tiated than under normal conditions. 



A closed-circuit respiration apparatus, S. I\I. Babcock and II. L. Kissell 

 ( Wisconsin Sta. Rpi. 1900, pp. 143-146, figs. 3). — A description is given of a form of 

 apparatus devised by the authors for conducting experiments in the respiration 

 of vegetable tissues, particularly for the study of the phenomena attending the 

 production of heat in silage. In the processes of their investigations it was found 

 desirable to economize in the jaroduction of gases used, which was accomplished by 

 the use of an apparatus in which a closed circuit permitted a limited quantity of gas 

 to be used over and over, with or without the addition of volatile substances. The 

 circulation of the gas was secured by utilizing a Bunsen inunp. Instead of the ordi- 

 nary Pettenkofer absorption tube, a special form of tube for the absorption of carbon 

 dioxid was used with good results. The tube presents numerous irregularities which 

 break up and hold the air, so that the carbon dioxid is more readily absorlied. 



A preliminary list of the Spermaphyta, seed-bearing- plants of North. Da- 

 kota, H. L. BoLLEY and L. R. W.\ldron [North Dakota Sta. Bui. 46, pp. 591-IJ81). — A 

 list is given of the seed-bearing plants of the State, in which 340 genera and 775 species 

 and varieties are enumerated. Notes are given on the economic value of many of 

 the species and their distribution throughout the State indicated. The principal 

 points of collection are shown upon a map of the State. 



Some Cercosporae of Macon County, Alabama, G. W. Carver {Alabama Tus- 

 Lcf/ee Sta. Bui. 4, pp. S). — A list is given of about 75 species of Cercosjiora, with their 

 host plants. 



Origin of the cultivated plants of Argentina, C. Lemee {Bol. Ofic. Ayr. Gan., 

 1 {WO I), Fih., pp. .i-f)). 



The improvement of agricultural cultivated plants, C. Fkchwirth {Die 

 Zi'ichtung der landwirtscliaftlichrn Knlturpjianzcn. Berlin: Paul Parey, 1001, pp. 

 X-\-270). 



ZOOLOGY. 



Infestation by mice and means for destroying them, G. Del Guercio {Nnore 

 Relaz. li. Staz. Ent. Ayr., l.ser., 1900, No. S, pp. 109-128, fig. 1). — It is reported that 

 Microtus terrestris is becoming annually more destructive in certain parts of Italy. 

 Experiments were made for the purpose of determining the most practicable means 

 of destroying these animals. Poisons which were used for this purpose included 

 arsenious aciil, arseniteand arsenate of potash, arsenite and arsenate of copper, sul- 

 phate of coj)per, and corrosive sublimate. The experiments were conducted under 

 conditions as near the normal as possible, fresh vegetation being sprinkled with solu- 

 tions of the poison. Arsenite of potash proved the most effective and arsenious acid • 

 came next in effectiveness. Good results were also obtained from the use of poison- 

 ous ga.sses, such as sulphurous anhydrid and bisuli)hid of carbon. 



Exjieriments were conducted in infecting mice with a disease due to ('uccobacitlns 

 mariinn, and under favorable conditions this method promi.ses favoi^'able results. 

 Detailed directions are given for the practical application of fluid poisons, gaseous 

 poisons, and the bacterial virus. 



