376 



SCIENCE. 



[N. S. Vol. XXIV. No. 612. 



having a sharp pointed Rod fix'd on the Top of 

 their Masts, with a Wire from the Foot of the 

 Rod reaching down, round one of the Shrouds, 

 to the Water, will not be hurt by Lightning. 



From the foregoing it is evident that Frank- 

 lin drew up definite instructions for erecting 

 lightning-rods before the close of the year 

 1752 and from the contemporaneous letter, 

 describing the electrical kite, it would appear 

 that at this time some edifices in Philadelphia 

 were thus equipped, but whether for their pro- 

 tection or for experiment is uncertain. 



A. Lawrence Eotch. 



Blue Hill Meteokological Obsebvatoby, 

 August 13, 1906. 



DRIED COTTON CULTURES ONCE MORE. 



It would appear from a recent communica- 

 tion in Science that the original dictum of 

 Messrs. Harding and Prucha that the nodule- 

 forming bacteria will not survive when dried 

 upon cotton is now to be modified to apply 

 only to those cultures dried (?) in a Petri dish 

 enclosed in a paper bag and stored in a drawer 

 or under conditions considered to be similar 

 to this. Although an attempt is made to show 

 that such a method closely resembles that used 

 in the original preparation of cotton cultures, 

 the actual difference in drying time will be so 

 evident to any one who cares to try the ex- 

 periment that it need not be discussed here. 

 Indeed, it would hardly seem necessary to 

 demonstrate the fact that of two pieces of 

 cotton containing the same amount of mois- 

 ture, one enclosed in a Petri dish, and the 

 other exposed to the action of an abundance 

 of warm air, the one in the air will dry 

 much sooner than the protected piece. One 

 would as readily expect clothes to dry as 

 rapidly enclosed in a box, wrapped in paper 

 and put away in a drawer as when hung upon 

 a line. In fact it was this very question of 

 rapidity of drying which caused the various 

 ' germ-proof ' methods of preparing the cotton 

 to be abandoned. It was found that even in 

 a specially constructed box of large size (ap- 

 proximately 8x2x2 feet) through which air 

 was forced over a warm coil, that the length 

 of time required for drying was entirely too 

 long, and for practical purposes, considering 



the way in which the cultures were to be used, 

 it was better policy to turn out a culture which 

 might be more or less contaminated than to 

 destroy the nodule-forming bacteria in an 

 attempt to produce a pure culture. Experi- 

 ments showed that all attempts, with the 

 facilities available, to produce absolutely pure 

 cultures upon cotton involved an unwarranted 

 sacrifice of efficiency. 



It has been supposed that the result ob- 

 tained by the users of the dried cotton cul- 

 tures would of itself be a sufficient refutation 

 of the statement that dried cotton cultures 

 were valueless. This seems to be the case 

 since an attempt is now made to explain the 

 reports received by users of the cultures upon 

 ' psychological ' grounds. 



If the bacteria will not live upon cotton 

 it is of course necessary to account in some 

 way for the thousands of satisfactory reports 

 received from this country and elsewhere, and 

 the psychological explanation would seem to 

 be as good as any. It should be remembered, 

 however, that many of the favorable reports 

 were furnished by those fully as competent 

 to judge of the results obtained as a member 

 of an experiment-station staff — that a con- 

 siderable number of these experiments were 

 checked by uninoculated plots and that photo- 

 graphs showing the difference between these 

 treated and untreated plots are available in 

 all cases where it was possible to obtain them. 

 Furthermore, the reports covered tests with 

 sterilized soil and sand as well as field experi- 

 ments. 



Since the publication of a few of the favor- 

 able reports first received, there have been 

 many others which emphasize even more 

 strongly the benefit derived from cultures when 

 used under the conditions for which they are 

 designed. During the past season, while the 

 statement that the cotton cultures were value- 

 less was very widely published, producing, one 

 would suppose, anything but a favorable psy- 

 chological effect, most satisfactory reports con- 

 tinued to be received. 



Although it is manifestly impossible in this 

 statement to refer directly to any of these 

 reports, it may not be out of place to cite 



