112 PEOCEEDIXGS OF THE 



like some of his Cambridge contemporaries, he had become dis- 

 satisfied with the methods of zoological reasoning then in vogue. 

 It was consistent with his sincerity of cliaracter and piu'pose that 

 he could not accept conclusions based upon what seemed to him 

 to be imperfect argument and insufficient evidence, and he found 

 that the mode of argumentation commonly in use, though ingenious, 

 was lacking in rigour of scientific proof. At this time a considerable 

 body of young naturalists was collected in the Plymouth Labora- 

 tory, and discussions on the validity of the doctrine of Natural 

 Selection were frequent. Weldon was ever a firm upholder of 

 Natural Selection, and in these discussions took up an attitude of 

 firm opposition to the theories of Eimer and the ueo-Lamarckiau 

 school. At the same time he could not give unqualified assent to 

 the brilhant speculations of AVeismann, then at the height of their 

 influence, finding them, like the rest of current morphological 

 speculation, too vague and too deficient in rigorous demonstration. 

 Being therefore dissatisfied with the methods he had hitherto 

 employed, Weldon turned his attention to the works of Francis 

 Gralton, and on reading these more attentively than he had done 

 before, was immediately attracted by the prospect of introducing 

 exact mathematical proof into zoological argument. The writer 

 well remembers his coming into the Plymouth Laboratory one 

 morning, armed with Galton's ' Natural Inheritance,' the contents 

 of which he forthwith proceeded to expound wuth his accustomed 

 eagerness. He pointed out that since the time of the publication 

 of the ' Origin of Species,' zoologists had blindly accepted Darwin's 

 conclusions, but, with few exceptions, had neglected Darwin's 

 methods. " Science," he said, " is measurement : Darwin made 

 use of measurement, and if we are to make any progress his 

 example must be followed." This was the turning-point of Weldon's 

 career. With characteristic energy he proceeded to apply to 

 animals the statistical methods used by Galton in anthropometric 

 researches, and as he was engaged at the time with the develop- 

 ment of the Shrimp, he chose this animal for his first essay in 

 what he afterwards called Biometrics. Collecting large numbers 

 of shrimps from three different localities, he found that the results 

 of his measurements confirmed what Gait on had established for man 

 and domesticated animals, and, further, that the " probable error" 

 of the same organ was different for the three groups of shrimps 

 from Plymouth, Southport, and Sheerness*. In other words, the 

 shrimps from these localities form three distinct races. Encouraged 

 by the success of his first effort, Weldon set to work to pre])are 

 himself for extended investigations of a like nature. Pinding 

 at the outset that his knowledge of statistics was insufficient, he 

 put himself through a course of mathematical study, and in a 

 short time was fully equipped for the prosecution of higher statistical 



* " Tiie Variations occurring in certain Decapod Crustacea. — I. Crangon 

 vulgaria," Proe. Royal See. vol. 47 (ls90). 



