716 EXPERIMENT STATION RECORD. 



lished between the gases. The author estabUshes the general proi^osition that fruits 

 and seeds whose reserve of sugar or similar substance is transformed into oil present 

 a respiratory quotient of unity or greater. This respiratory quotient shows the trans- 

 formation of mannite or of glucose to oil in the fruit or organ which contains it. The 

 studies further showed that temperature, wounding of the fruit, etc., influenced the 

 formation of oil and consequently the respiratory quotient. It is said that in the 

 south of France the reserve material which is transformed into oil is mannite, while 

 probably in more northerly regions it is to be compared with glucose. In this respect 

 there is some variation in the ripening of olives in different regions, but in the forma- 

 tion of acids, alcohol, ethers, etc., the phenomena observed are quite constant. 



The influence of alkaloids on the respiration of plants, N. Morkowine {Rev. 

 Gen. Bot., 13 {1901), Nos. 147, pp. 109-H6; 14S, pp. 177-192; 149, pp. 212--226; 150, pp. 

 265-275). — A report is given of an extended series of investigations on the effect of 

 various alkaloids as shown in the respiration of plants. The subjects of the experi- 

 ments were young shoots and etiolated leaves of Vidafaba. This plant was selected 

 on account of its well-known intensity of respiration and the presence of a consider- 

 able amount of albuminoids. The leaves and young shoots were arranged in 2 

 series and placed in a sugar solution, and after remaining in this for 2 or 3 days 

 one lot was removed and placed in a similar solution to which a definite amount of 

 alkaloids had l)een added. The 2 lots of plants were then placed under identi- 

 cal conditions of light, temperature, etc., and the differences as shown by the respi- 

 ration determined. The carbon dioxid exhaled by the plants was determined by 

 means of a Pettenkofer apparatus. In the long series of experiments an increased 

 respiration was noticed where the alkaloids were added to the solution, and in most 

 cases an increase was shown in the ash of the plants at the end of the experiment. 



The author's experiments further showed that the alkaloids presented toxic influ- 

 ences toward the plants similar to those shown by animal organisms. An important 

 difference, however, is noted in the relative toxic properties. Arranged in order of 

 the most poisonous toward plants the alkaloids were as follows: Quinin, cinchonin, 

 caffein, morphin, cocain, strychnin, atropin, antipyrin, brucin, codein, and pilo- 

 cai'pin. These were not poisonous in dilute solutions except after a considerable 

 exposure. Of all the substances experimented with the hydrochlorate of quinin was 

 the most i^oisonous. 



Poisonous action of mercury on green plants, J. W. Dafert {Ztschr. Landw. 

 Versuchsw. Oesterr., 4 {1901) , No. 1, jjp. 1-10; abti. in .hm. Agron., 27 {1901), No. 7, pp. 

 350-352). — The author has made a study of the action of the fumes of mercury on green 

 plants, using in his experiments wheat, barley, rye, oats, clover, pine, aster, white 

 mustard, and verbena. All the plants studied showed a great sensitiveness to the 

 vapors of mercury, young plants being less resistant than older ones. The poisonous 

 action is manifested by tlie destruction of the chlorophyll-bearing organs, especially 

 in the young leaves, where it seems to check assimilation. The root system of the 

 plants seems to l)e affected to a less degree, plants lieing able to grow in soils contain- 

 ing a considerable quantity of metallic mercury. Hunudity favors the action of 

 mercury, especially in herbaceous plants. On account of the frequent use of mercury 

 in various physiological investigations, the author recommends that the surface of 

 the mercury should always be covered by a film ^A glycerin, which checks the forma- 

 tion of vapor. Water and mineral oils do not seem to be as efficient in this respect 

 as glycerin. 



Fixation of metals by cell walls of plants, H. Devaux {Compt. Itind. Acad. Sci. 

 Paris, 133 {1901), No. 1, pp. 58-60). — By placing petioles of Aralia and young stems 

 of Sambucus and of cucurbits in solutions containing various metals, after which the 

 stems were examined spectroscopically, the author was able to note the presence in 

 appreciable quantities of potassium, lithium, sodium, calcium, strontium, barium, 

 iron, nickel, cobalt, cadmium, copper, lead, and silver in the cell walls of the {)lants; 



