August i i, 1923] 



NATURE 



205 



lation coefficient for the sun-spot effect on the 

 diurnal-variation (range, average departure, Fourier 

 combined amplitude) of the potential gradient for 

 various stations is about o-8 ; for Ebro and Eskdale- 

 muir it exceeds o-g. The reason that Dr. Chree 

 gets somewhat unsatisfactory results from certain 

 diurnal data at Kew is partly because of the fact, 

 already mentioned, that Kew is not a favourable 

 station for the most successful study of world effects. 

 However, applying a formula similar to (i) to the 

 Kew series 1 898-1 909, Dr. Chree's correlation 

 coefficient for the sun-spot relation of his quantity c^ 

 (combined amplitude of the 24-hour and 12-hour 

 waves of the Fourier series) is increased from 0-46 to 

 0-77 ; s = 4-0-50 percent., and t ^ - 2-11 percent, of c^. 



The sun-spot influence is also shown in the annual 

 variation of the potential gradient at Ebro, for the 

 period 1910-1921 ; the correlation coefficient is 071. 



General Conclusion. — -The relationship between 

 sun-spot activity and atmospheric electricity turns 

 out to be, for locally undisturbed stations, as definite 

 as in the case of terrestrial magnetism ; the sun-spot 

 influence on the periodic variations of the atmospheric 

 potential-gradient is, in general, as great as on the 

 periodic variations of terrestrial magnetism ; and 

 as concerns the effects on the absolute values, the 

 sun-spot influence is about 300 times greater in 

 atmospheric electricity than in terrestrial magnetism. 

 The potential gradient of atmospheric electricity, 

 and, presumably, the earth's total negative electric 

 charge, is furthermore subject to an annual or 

 secular change, which may vary in magnitude and 

 sign from one sun-spot cycle to another. 



Louis A. Bauer. 



Department of Terrestrial Magnetism, 

 Carnegie Institution of Washington, 

 Washington, D.C., June 7. 



Use of Yeast Extracts in Diabetes. 



In a previous letter to Nature of March 10 (iii, 

 p. 327) we stated that we had obtained from yeast 

 an insulin-like substance which had the effect of 

 lowering the blood sugar of normal animals. Later 

 we described the beneficial effect of this extract on 

 some cases of diabetes mellitus {Brit. Med. Journ. 

 i. p. 711, 1923). We soon found that the activity of 

 the extract from different samples of yeast varied 

 very widely. The results of these experiments will 

 be published at a later date in conjunction with Dr. 

 H. B. Hutchinson. In this connexion it is of interest 

 to note that Collip (Proc. Soc. of Exp. Biol, and Med., 

 20, p. 321, 1923) reports numerous failures before he 

 succeeded in obtaining an active extract from yeast, 

 and later Funk and Corbitt (Proc. Soc. of Exp. Biol, 

 and Med., 20, p. 422, 1923) have met with similar 

 variability. 



We have recently obtained from the action of 

 micro-organisms other than yeast extracts which 

 have a very considerable power of lowering the blood 

 sugar of normal animals to a point where convulsions 

 occur. That the convulsions were not due to a toxic 

 effect is shown by the fact that they were relieved by 

 injection of glucose. The extract like that from 

 yeast caused the blood sugar to be lowered for a 

 much longer time than when insulin was used. 

 Whether these extracts will be of practical import- 

 ance remains to be decided. Experiments are being 

 directed to this end. 



L. B. Winter. 

 W. Smith. 



Biochemical Laboratory, Cambridge, 

 July 20. 



NO. 2806, VOL. I 12] 



Tenacity of Life of an Eel. 



I HAVE lately had occasion to notice a further proof 

 of the tenacity of life exhibited by the eel, which 

 may perhaps be of interest. 



A correspondent in America, Mr. L. L. Mowbray, 

 of the Aquarium, Battery Park, New York City, has 

 kindly sent me from time to time specimens of elvers ^ 

 of the American eel, preserved in formol, for in- 

 vestigation purposes. Quite recently, a parcel from 

 Mr. Mowbray was delivered at the laboratory here. 

 Greatly to our surprise, however, instead of elvers 

 preserved in formol as usual, it proved to contain a 

 single specimen very much alive. 



The little eel was enclosed in a small glass bottle 

 (quarter-litre size) , which had been corked and waxed 

 so as to render it perfectly air-tight, and the bottle 

 again enclosed in one of the tin cylinders commonly 

 used in the United States for sending natural history 

 specimens by post. The tiny creature had thus made 

 its voyage across the Atlantic in complete darkness, 

 and without any renewal of air in the 200 c.c. of 

 water in which it was originally placed. 



The postmarks showed that it had left New York 

 on April 19, and arrived in Copenhagen on May 19, 

 1923. It has now been transferred to a small 

 aquarium, where it is still alive and active, to all 

 appearances in excellent form after its lengthy 

 journey. 



Evidently, then, the American fresh-water eel is by 

 no means inferior to its European cousin in respect 

 of endurance and tenacity of life. 



I may add that we have, at the Laboratory here, 

 two live adult specimens of the American eel. They 

 have been in our aquaria since 1914, when we brought 

 them home, as elvers, from Santa Cruz, in the West 

 Indies. They, however, made the journey in an open 

 beer bottle, with frequent changes of water, and v.ere 

 thus not subjected to so severe a test of endurance 

 as the specimen above mentioned. 



JoHS. Schmidt. 



Carlsberg Laboratory, Copenhagen, 

 June 28. 



Adsorption on Soil-Grains. 



The recently published work by Messrs. J. Hendrick 

 and G. Newlands {Journ. Agric. Sci., January 1923) 

 on the mineral particles in the coarser grades of the 

 " fine earth " separated from soils was noticed in 

 Nature of June 9, p. 736, and it was remarked that 

 "the study of adsorptive reactions should not be 

 entirely restricted to the colloidal field." 



It is of interest to note that the United States 

 Department of Agriculture took up this question last 

 year, and its Bulletin No. 1122 (October 21, 1922) 

 records the work of Messrs. M. S. Anderson, W. H. 

 Fry, P. L. Gile, H. E. Middleton, and W. O. Robinson, 

 on " Absorption by colloidal and non-colloidal soil 

 constituents." The authors worked on material finer 

 than 2 mm. in diameter, which, in common with so 

 many experimenters, they call " the soil," by an 

 unfortunate restriction of the term. This earth is 

 separated, preferably by centrifugal methods, into 

 three grades, 2 000-0-050 mm., 0-050-0-001 mm., and 

 less than o-ooi mm., the last being styled colloidal. 

 In testing the relative powers of adsorption on (or 

 absorption by) these grades, it was justly felt that 

 samples really free from colloidal matter could be 

 best obtained by crushing unaltered minerals. In 



' The youngest stages of eel-fry which make their way up into fresh 

 water are called elvers. 



F 2 



