840 EXPERIMENT STATION RECORD. 



well-nourished cultures light had no effect on respiration. With old cultures the 

 action of light promoted respiration. The effect of light usually became apparent in 

 about 30 minutes and continued as long as the conditions remained constant. By 

 repeatedly changing from light to darkness the flasks in which the organisms were 

 grown, the stimulating influence of the light was greatly diminished. With Mucor 

 stolonifer light had a positive stimulating effect for the first half hour, but if contin- 

 ued much beyond that time it proved detrimental to the resijiration of the mold. 



Investig-ations on the respiration of plants, B. Plovtzev {Zap. Imp. Akad. 

 Nauk, 22 {1901), Xo. 7; abs. in Zhnr. OpiiiliL Agnm. [Jour. Rxpt. Lanchv.'], 3 [1902), 

 No. 2, pp. 233-237). — A critical review is given of investigations relating to the sub- 

 ject of plant respiration. — p. fireman. 



The irritability of stigmas as a means for the prevention of the germina- 

 tion of foreign pollen, W. BuRCK {Pror. Sec. Sci., Koninkl. Akad. WetenscJt. Am.^ter- 

 dam, 4 {1901-2), p[>. 184-193). — The results of a study of the irritable stigmas of 

 Torenia fournierl and of 3fimidus luteus are given, in \\'hich comparisons are made 

 with a number of other plants possessing broad stigmas which are more or less sensi- 

 tive. As a result of these studies the author claims that the movements present in 

 the stigmatic lips serve to protect the flowers against the entrance of foreign pollen. 

 In a number of experiments he found that the pollen of other species would germi- 

 nate upon the stigmas of a given plant, but by the rapid closing of sensitive stigmatic 

 surfaces the lial)ility to fecundation was greatly reduced. If pollen from the same 

 species be placed upon the stigmatic surfaces the lobes closed and opened only after 

 a considerable duration of time, if at all, while if mechanical stimulus or foreign 

 pollen be i)resent the stigmas reopen within a quarter of an hour. 



The necessity of lime for seedlings, especially those grown at high tem- 

 peratures, L. VON PoRTHEiM {Sltzher. K. Akad. irm. Math. Naturir. CI. []'ienna'\, 

 110 {1901), Xo. 4, J>p- 113-157). — After reviewing and discussing considerable liter- 

 ature on the role of lime in plant nutrition, the author gives an account of experi- 

 ments with seedlings of peas, lentils, beans, vetches, castor beans, flax, buckwheat, 

 poppy, hemp, sunflower, pine, larch, and various cereals to ascertain the effect of a 

 lack of lime in the media in "vvhich the plants were grown. After sprouting the seed 

 between blotters wet with distilled water, the seedlings were transferred to pots con- 

 taining clay shale and nutrient solutions added that varied only in the presence or 

 absence of calcium nitrate. The plants were watered from time to time with spring 

 or distilled water, dependent on the presence of lime in the nutrient media used. 

 The growth of the different seedlings was noticed daily, especially the effect of rais- 

 ing the temperature to from 30 to 35° C. In many cases, but not all, the develop- 

 ment of the hypocotyl and roots was much greater in the pots containing lime. The 

 peculiar feature of nearly all the experiments was the turning brown and dying of 

 the roots of the seedlings grown in the pots which had received no lime. In the 

 case of the leguminous seedlings this took place within a few days. All the plants 

 after a time became weakened and diseased, and the time difference between the 2 lots 

 was assumed to show the necessity for lime for that particular plant. Increasing the 

 temperature showed a marked effect on the condition of the 2 lots of plants, those 

 without lime apparently suffering the most. 



According to the author, his experiments show that the presence or absence of 

 lime is immaterial for seedlings of cress, sorrel, rye, barley, wheat, oats, larch, and 

 pine. The injurious effect of the absence of lime, as shown by Schimper, is attrib- 

 uted to the great quantity of potassium oxalate which is deposited within plants 

 grown in the absence of lime. A brief bibliography completes the paper. 



The solvent power of plants for mineral phosphates {Rev. Gen. Acjron. 

 \_Louv(tin'], 11 {190.i), Xo. 7-S, pp. o37-34J)-—The results of an extended series of 

 experiments with a large number of sjjecies of i)lants are given, from which it api>ears 

 that the solvent power of mineral phosphates varies widely with different classes of 



