422 



SCIENCE 



[Vol. LV, No. 1425 



This made the cell theory of Schleiden and 

 Schwann a possibility. 



Without detracting at all from the epoch- 

 making work of these two men, and with gi'eat 

 admiration for that of Schwann, who accurately 

 described for the first time many types of ani- 

 mal cells, the present writer finds himself un- 

 able to give them sole credit for a theory that 

 had been taught forty years earlier in France. 



Not one of these pioneers knew how new 

 cells originate. It was the deep secret that 

 most intrigued the active minds of the two 

 Germans. They made their guess, and guessed 

 wrongly, but their observations in confirmation 

 of Robert Brown's important discovery, and 

 Schwann's clear pictures of animal cells, have 

 given them the distinguished place that they 

 deserve among the founders of the cell theory. 

 Whether they should be given exclusive credit 

 for the theory that had been taught in Paris 

 forty years earlier by Lamarck, and admirably 

 supported by beautiful plates prepared by Mir- 

 bel showing plant structures, the reader may 

 judge for himself by reading a review of the 

 whole situation in the current number of The 

 Seientific Monthly^, and, better, by perusing 

 the original books and papers to which refer- 

 ence is therein made. 



Reviewed now, after the lapse of a century, 

 the different methods and temperaments of the 

 various writers are thrown into bold relief, and 

 one is forcibly reminded of the folly of un- 

 checked speculation and the wisdom of guard- 

 ing the indispensable imagination by keen, un- 

 tiring observation and experiment. 



John H. Geeould 

 Dartmouth College 



SCIENTIFIC EVENTS 

 DISINTEGRATION OF ELEMENTSi 

 I HAVE been asked to say a few words about 

 a telegram in the Times of March 14 giving an 

 account of a paper communicated to the Amer- 

 ican Chemical Society at Chicago by Dr. G. 

 Wendt and Mr. C. E. Iron. It reported that, 



1 Tlie Dawn of tlie Cell Theory, Scientific 

 Monthly, Vol. XIV, No. 3, pp. 268-277, March, 

 1922. 



1 Sir Ernest Eutherf ord, in Nature. 



when a powerful condenser discharge at 100,000 

 volts was sent through a very fine tungsten 

 wire, the filament exploded with a "deafening 

 report," producing a flash estimated to cor- 

 respond to a temperature of at least 50,000° F. 

 The telegram states: "After the flash he (Dr. 

 Wendt) found atoms of tungsten decomposed 

 into simpler atoms and the result Avas the 

 change of metallic tungsten into gaseous 

 helium." The experiments were made to inves- 

 tigate whether any atomic disintegration can 

 be effected by svich high temperature dis- 

 charges, and apparently the authors believe 

 that they have obtained positive results. 



We must await a much fuller account of the 

 experiments before any definite judgment can 

 be formed; but it may be of interest to direct 

 attention to one or two general points. During 

 the last ten years many experiments have been 

 recorded in which small traces of helium have 

 been liberated in vacuum tubes in intense elec- 

 tric discharges, and it has been generally 

 assumed that this helium has been in some way 

 occluded in the bombarded material. On mod- 

 ern views, we should anticipate that the disin- 

 tegration of a heavy atom into lighter atoms, 

 e. g., into atoms of helium, would be accom- 

 panied by a large evolution of energy. Indeed, 

 it is to be anticipated that the additional heat- 

 ing effect due to this liberated energj' would be 

 a much more definite and more delicate test of 

 disintegration of heavy atoms into helium than 

 the spectroscope. 



Our common experience of the large effect of 

 temperature in ordinary chemical reactions 

 tends to make us take a rather exaggerated 

 view of the probable effects of high tempera- 

 tures on the stability of atoms. While it seems 

 quite probable that momentary temperatui'es of 

 50,000° F. can be obtained under suitable con- 

 ditions in condenser discharges, it should be 

 borne in mind that the average energy of the 

 electrons in temperature equilibrium mth the 

 atoms at xliis temperature corresponds to a fall 

 of potential of only 6 volts. In many physical 

 experiments we habitually employ streams of 

 electrons of much higher energy and yet no cer- 

 tain trace of disintegration has Ijeen noted. In 

 particulai-, in Coolidge tubes an intense stream 

 of electrons of energy about 100,000 volts is 



