VALEDICTORY ADDRESS. XI 



Thompson's assertions ; but, so far as my own observations 

 allowed me to form an opinion on the subject, I was ever in- 

 clined to think that this gentleman merited well of science, 

 which is far more than could be said of any of those persons 

 who, by crude inferences, but oiever hy direct observation, have 

 ventui'ed to attack him."'' With a candid acknowledgment 

 that I have never proved by demonstration the truth of Dr. 

 Thompson's assertions, I wish to take this opportunity of 

 expressing my perfect and entire belief in the whole of his 

 statements. I cannot understand on what grounds any casual 

 commentator is to overthrow statements resulting from a long 

 and laborious investigation. Before the evidence of so dili- 

 gent an observer as Dr. Thompson can be in the least shaken 

 in the minds of the unprejudiced, a series of careful experi- 

 ments must be formed, a series of rigid results noted, and the 

 statements now existing must be met by counter-statements of 

 equal weight. Has this been the case ? Do we not, on the 

 contrary, find that investigation corroborates, rather than invali- 

 dates, these important assertions? Mr. MacLeay unhesitat- 

 ingly says, that Captain Ducane, R. N., who has made at 

 Southampton most interesting observations on the metamor- 

 phosis of Crustacea, has confirmed Thompsons observations. 

 Although confirmation is always desirable, and sets the matter 

 more thoroughly at rest, yet I confess that Dr. Thompson's 

 unsupported statements carry perfect conviction to my mind. 

 His conclusions rest not on isolated or accidental observations, 

 but on elaborate researches, conducted with scrupulous care. 

 In his Memoir on Pinnotheres,^ Dr. Thompson states that he 

 kept alive those females which had large bunches of ova, and 

 that he actually " saiv the ova hatch hi great numbers, under 

 the form of a new kind of Zoc" This is no expression of 

 opinion, no proposition of a theory, but a statement of a posi- 

 tive fact. I cannot appreciate highly the feeling that would 

 quash this assertion. It seems to me that Dr. Thompson's 

 statements are not to be shaken by doubts or arguments. 



<= Illustrations of the Zoology of South Africa; Annuiosa, p. 5S. 

 ^ Entoir.ological Magazine, Vol. III. p. 88. 



