December 12, 1912] 



NATURE 



4'3 



have seen of the method, it can scarcely be a modi- 

 fication of the "immune body" treatment, with 

 which, it is maintained, some success has been 

 attained. It appears more hkely that we 

 have to deal with some modification of Calmette 

 and Guerin's method, in which the bovine 

 tubercle bacillus is cultivated on a glycerinated 

 medium to which a small proportion of ox-bile has 

 been added. Here, after about forty generations 

 of such culture, the bacillus becomes so far modi- 

 fied that when injected intravenously into the 

 bovine animal it is incapable of setting- up an active 

 tuberculous process, and so modifies the tissues 

 and especially the wall of the alimentary canal of 

 the treated animal that an ordinary culture of a 

 virulent "bovine" bacillus is no long-er able to 

 retain its position in the tissues of the host, and, 

 consequently, is unable to set up any tuberculous 

 process. 



It is, of course, too early to pronounce any 

 definite opinion, either favourable or adverse, on 

 these various methods. It must be realised that a 

 certain proportion of the cases in which there is 

 tuberculous infection recover without any special 

 treatment ; that others recover when supplied with 

 plenty of fresh air, g-ood food, and when the 

 hyg-ienic conditions generally are favourable, and 

 that these agencies are called into plav by all who 

 are engaged in the intelligent study and treat- 

 ment of tuberculosis. 



SIR GEORGE HOWARD DARWIN, K.C.B.. 

 F.R.S. 



GEORGE DARWIN, whose decease occurred 

 at Cambridge on Saturday, December 7, 

 came, as is well known, of illustrious scientific 

 lineage, having been born in 1845 at Down, the 

 second son of Charles Darwin, author of "The 

 Origin of Species," and thereby the renovator of 

 the biological sciences. Like many contem- 

 poraries who attained to distinction in scientific 

 pursuits, his school education was gained under 

 the Rev. Charles Pritchard, F.R.S., afterwards 

 Savilian professor of astronomy at Oxford. He 

 went up to Trinity College, Cambridge, in 1S64, 

 graduated as second wrangler and second Smith's 

 prizeman in 1S68, the present Lord Moulton being- 

 senior; he was elected a fellow of Trinity the 

 same year, and enjoyed the statutory tenure of 

 ten years. In addition to mathematical subjects, 

 he was interested in economic and political 

 science, and with a view to practical life was 

 called to the Bar in 1874. About this time he 

 wrote a well-known statistical memoir on the 

 marriage of first cousins, an early example of 

 the present exact investigations in cognate bio- 

 logical domains. Considerations of health, how- 

 ever, prompted his return to Cambridge, where 

 he devoted himself to mathematical science, 

 especially in its astronomical aspects. He had 

 already initiated his most striking contributions 

 to the subject of the evolution of the solar system, 

 especially the moon-earth system, and to 

 cosmogony in general, when he was elected to 

 NO. 2250, VOL. 90] 



the Plumian chair of astronomy and experimental 

 philosophy in 18S3. He was re-elected fellow of 

 Trinity, as professor, in 1884, and his marriage* 

 dates from the same year. 



If one were asked to name a domain in which 

 the power of mathematical analysis had con- 

 spicuously asserted itself over phenomena ap- 

 parently most complex and fortuitous, the predic- 

 tion of the tides up to their closest details, by 

 procedure now systematised so that it can be 

 applied almost without technical skill, would 

 surely come to mind. The principles of the ap- 

 plication of harmonic analysis to this subject were 

 laid down by Laplace, following up the beginnings 

 established long before by Newton ; but it was a 

 far cry from this to actual systematic perform- 

 ance. The outstanding name in this magnificent 

 achievement is that of Lord Kelvin, whose intel- 

 lectual energy kept the subject to the fore, while 

 his inventive genius originated the machines by 

 which calculations too long and laborious for 

 arithmetical processes were reeled off auto- 

 matically. But it is very doubtful whether tidal 

 practice, in which British methods dominate the 

 world, or the refinements of tidal theory, would 

 stand in their present completeness if Kelvin had 

 not enjoyed the good fortune, when he was him- 

 self getting submerged in other problems, of 

 finding a colleague so imbued with the subject, so 

 expert and tenacious amid the complexities of 

 numerical calculation, as George Darwin proved 

 himself to be. His tribute to Lord Kelvin, to 

 whom he dedicated volume i. of his Collected 

 Scientific Papers, which relates to this subject, 

 gave lively pleasure to his master and colleague : — 



Early in my scientific career it was my good fortune 

 to be brought into close personal relationship with 

 Lord Kelvin. Many visits to Glasgow and to Largs 

 have brought me to look up to him as my master, 

 and I cannot find words to express how much I owe 

 to his friendship and to his inspiration. 



The practical developments of tidal theory and 

 prediction were published to the world in a series 

 of reports to the British Association, worked out 

 mainly by Darwin, from the year 1883 onward. 

 In 1879 he had broken ground in another direc- 

 tion, entirely fresh. The recognition of lunar 

 tidal friction as a cause of lengthening of the 

 day goes back to Kant. The problem as to how 

 the tidal loss of energy is divided between the 

 earth's rotation and the lunar orbit had baffled 

 Airy; it had been shown by Purser that the prin- 

 ciples of energy and momentum conjointly can 

 lead to its solution ; but it remained for Darwin 

 to develop, by aid of graphical representations 

 which have become classical, most striking infer- 

 ences regarding the remote past history of our 

 satellite. This discovery was the starting point of 

 a series of memoirs in the next subsequent years, 

 which applied similar procedure to the precession 

 of the equinoxes and to other features of the solar 

 system. 



In the later years of last century, during Lord 

 Kelvin's meteoric visits to Cambridge to attend 

 the annual meetings of the Fellows of Peterhouse, 



