72 



SCIENCE. 



[N. S. Vol. XXIII. No. 576. 



may call conveniently this whole process: origin 

 of species, 



I then proceed to characterize these four fac- 

 tors, which are the following: (1) variation; 

 (2) inheritance of variations, ' consanguinity 

 becomes morphologically visible'; (3) natural 

 selection, acting upon the material produced 

 by variation and inheritance, improving the 

 average, and causing, under certain circum- 

 stances, ' mutation ' ;° (4) ' bionomic separa- 

 tion ' (p. 190, I. c), forming what we call 

 ' species.' 



The four factors named, variation, inheritance, 

 selection and separation, must work together in 

 order to obtain different species; * * * it is im- 

 possible to think that one of them should work by 

 itself, or that one could be left as'ide. 



I have further demonstrated in the paper 

 referred to, that Darwin already held prac- 

 tically the identical opinion, although he did 

 not properly recognize ' bionomic separation,' 

 and introduced, in its place, the 'principle of 

 divergence.' In the face of this fact, it is 

 only to be regretted that bionomic separation 

 or habitudinal segregation has not received 

 due attention, and is generally not understood 

 in its true meaning by those that have little 

 experience in field work; indeed, it is impos- 

 sible to get an appropriate idea of it in the 

 museum or the laboratory, and also the bo- 

 tanical garden is entirely unfit to bring home 

 its significance. I hope, however, that its 

 real value and real meaning will become more 

 generally known by and by. For those that 

 have no chance to convince themselves in 

 nature of the ever-presence of bionomic sepa- 

 ration, the study of Gulick's book will be 

 advantageous. E. A. Obtmann. 



Pittsburg, Pa, 



SPECIAL ARTICLES. 



REACTIONS IN SOLUTIONS AS A SOURCE OF E.M.F. 



Permit me to call to the attention of the 

 readers of this journal certain observations 

 which I have recently made relative to the 

 chemical reactions in solution as a soutce of 



° Not the ' mutation ' of de Vries, which term 

 is decidedly ill chosen, being preoccupied long ago 

 by Waagen, Neumayr and W. B. Scott, and used 

 in an entirely different sense. 



the electric current. So far as I am informed 

 the phenomenon described below has not pre- 

 viously been recorded. 



Some time ago, while carrying on a series of 

 experiments upon photo-electric effects, certain 

 features of the investigation led me to suspect 

 that any and all chemical reactions give rise 

 to a measurable quantity of electrical energy. 



In order to test this I introduced into a very 

 small glass vessel two platinum wires. No. 26, 

 to serve as electrodes. These electrodes were 

 as nearly identical in dimensions as it was 

 possible to make them. They extended down 

 into the cell about two centimeters, at a dis- 

 tance apart of, perhaps, two millimeters. The 

 cell thus constructed held approximately 3 c.c. 

 The electrodes were then connected by means 

 of a short wire to a sensitive galvanometer. 



About 2 c.c. of silver nitrate solution (5 :25) 

 were introduced into the cell. Two Or three 

 drops of concentrated HCl were then added to 

 the silver solution in the cell. Immediately 

 when the acid came in contact with the salt 

 a decided deflection was manifest on the in- 

 strument. Stirring the reacting bodies in- 

 creased the deflection and at times reversed 

 the direction of the current. The maximum 

 deflection was about twenty-five scale divisions. 



At first the acid was introduced between the 

 platinum electrodes. Later it was found that 

 if the reagent was allowed to come in contact 

 with the silver solution about either one of the 

 electrodes the direction of the resulting cur- 

 rent, as indicated by the galvanometer, could 

 be predicted, i. e., the current in all cases left 

 the cell by that electrode about which the 

 reaction was taking place least vigorously. 



Different concentrations of the salt and acid 

 were tried. It was found that the deflection 

 of the needle was roughly proportional to the 

 concentration of the reacting bodies. It was 

 also observed that the current ceased when the 

 reaction was complete, which, when the solu- 

 tion was not stiii-ed, took at times a minute 

 or more. 



Other combinations were tried as follows : 

 NaCl and H,SO,; BaCl and H,SO,; CuSO. 

 and NH.OH; KOH and HCl. Each of the 

 above reactions gave rise to a decided deflec- 

 tion of the needle, the current continuing 



