THE ARGUMENT APPLIED. 47 



ments may seem to prove that the part is not necessary ; oi 

 may leave a doubt how far it is even useful to the plant or 

 animal in which it is found. This is said to be the case 

 with the spleen, which has been extracted from dogs with- 

 out any sensible injury to their vital functions. Instances 

 of the former kind, namely, in which we cannot explain the 

 operation, may be numerous ; for they will be so in propor- 

 tion to our ignorance. They will be more or fewer to difier- 

 ent persons, and in different stages of science. Every im- 

 provement of knowledge diminishes their number. There 

 is hardly, perhaps, a year passes that does not, in the works 

 of nature, bring some operatic*!}, or some mode of operation, 

 to light, which was before undiscovered — probably unsus- 

 pected. Instances of the second kind, namely, where the 

 part appears to be totally useless, I believe to be extremely 

 rare ; compared with the number of those of which the use 

 is evident, they are beneath any assignable proportion, and 

 perhaps have been never submitted to a trial and examina- 

 tion sufficiently accurate, long enough continued, or often 

 enough repeated. No accounts which I have seen are sat- 

 isfactory. The mutilated animal may live and grow fat — 

 as was the case of the dog deprived of its spleen — yet may 

 be defective in some other of its functions, which, whether 

 they can all, or in what degree of vigor and perfection, be 

 performed, or how long preserved without the extirpated, 

 organ, does not seem to be ascertained by experiment. But 

 to this case, even were it fully made out, may be applied 

 the consideration which we suggested concerning the watch, 

 namely, tlmt these superffuous parts do not negative the 

 reasoning which we instituted concerning those parts which 

 are useful, and of which we know the use ; the indication of 

 contrivance, with respect to them, remains as it was before. 

 III. One atheistic way of replying to our observations 

 upon the works of nature, and to the proofs of a Deity whicli 

 we think that we perceive in them, is to tell us that all 

 whidi wc sec must necessarily have had some form, and 



