26 EXPERIMENT STATION RECORD. 



the cathodic liquor of potassium nitrate favored leaf growth more than the 

 unelectrolyzed solution. For mixtures of potassium and sodium chlorid the 

 unelectrolyzed solution gave the best results. 



In experiments carried on with Mucor the anodic solutions gave the best 

 development, indicating that the protoplasm of the fungus differs somewhat 

 from that of higher plants. 



Filtering the solutions had practically no effect on their activity. 



Concerning' the action of an alternating current on germination, H. 

 MiCHEELS and P. De Heen (Acad. Roy. Belg., Bid. CI. Sci., 1910, No. 8, ;;p. 

 665-668). — In continuation of the above investigations, the authors compared 

 the effect of galvanic currents of high and low frequency, previous results hav- 

 ing showed a favorable action for an alternating current of high frequency. 



In the present paper it is shown that a continued galvanic current had a 

 detrimental effect on germination. A weak alternating current from 6 Daniell 

 cells did not favor the growth of roots or weight of seedlings, but it did cause 

 an increase in the length of the leaves. Where the current was increased the 

 results were comparable with those obtained by cathodic solutions, as explained 

 above. 



The effect of salts on the respiration of plants, A. Reinhard {Ber. Dent. 

 Bot. Gesell., 28 {1910), No. 9, pp- Jt51-k55). — In continuation of some previous 

 experiments (E. S. R., 24, p. 328), the author has repeated his experiments with 

 peas, testing the effect of a number of salts in solutions upon the respiration Of 

 the ground pea seed. Peas of the variety Victoria were ground and mixed with 

 distilled water and salt solutions until a thick paste was formed, after which 

 the respiration was investigated. 



Neither potassium nitrate, potassium phosphate, magnesium sulphate, calcium 

 nitrate, nor iron chlorid in dilute concentrations had any effect on the respira- 

 tion of the ground seed, even when the experiment was prolonged for a con- 

 siderable time. Potassium nitrate and calcium nitrate showed no stimulating 

 effect but rather had an injurious influence on the respiratory enzyms. 



Origin of osmotic effects. — III, The function of hormones in stimulating 

 enzymic change in living structures, H. E. and E. F. Armstrong {Proc. Roy. 

 8oc. [Londo7i], Ser. B, 82 (1910), No. B 559, i>p. 588-602; abs. in Jour. Chcm. 

 Soc. [London], 98 (1910), No. 516, II, pp. 883, 88-i).—lt has been shown that 

 when a leaf of cherry laurel is exposed to the vapor of an anesthetic, hydrogen 

 cyanid is liberated, and that not only the common anesthetics but many organic 

 vapors have a similar effect. Weak solutions of mineral acids, alkalis, and 

 salts are inactive, but the simpler organic acids all pass into the leaf from 

 solutions. The behavior of the laurel leaf resembles very closely that of the 

 barley grain (E. S. R., 21, p. 126). 



It is proposed to divide substances other than colloids into 2 classes, according 

 as they will or will not pass through the differential septa, such as occur in the 

 barley grain and the laurel leaf. For those that will pass through the septa 

 the term " hormone " has been suggested. 



Experiments show that water passes into the leaf together with the hor- 

 mone, and the hypothesis is advanced that, when introduced into the living cell, 

 substances which are not attractive to water exercise stimulative effects that 

 are primarily mechanical. The molecules of the hormone are interposed be- 

 tween the molecules in the cell by the change in the osmotic state, and an influx 

 of water from other regions takes place. It is thought that probably the mere 

 dilution thus effected is determinative of any changes produced. Degenerative 

 changes which are set up tend to increase in intensity as the products of change 

 exercise a stimulative influence, and gradually enzyms are set free which can 

 attack the various hydrolytes stored in the cell. 



