animals becomes so much evidence of natural selection having slowly formed the animals to appropriate the nutrition which the plants had previously gathered--and gathered under the previous influence of natural selection acting on themselves entirely for their own sakes. Therefore I say it is painfully manifest that "the enchainment of all the various orders of creatures in a hierarchy of activities," is _not_ "in harmony with what we might expect to find in a world the outcome of a First Cause possessed of intelligence and [beneficent] will." So far as any argument from such "enchainment" reaches, it makes entirely against the view which Mr. Mivart is advocating. In point of fact, there is a total absence of any such "ministration" by one "order of creatures" to the needs of any other order, as the beneficent design theory would necessarily expect; while such ministration as actually does obtain is exactly and universally the kind which the naturalistic theory requires. Again, quite independently, and still more recently, Mr. Mivart alluded in _Nature_ (vol. xli, p. 41) to the difficulty which the apparently exceptional case of gall-formation presents to the theory of natural selection. Therefore I supplied (vol. xli, p. 80) the suggestion given in the text, viz. that although it appears impossible that the sometimes remarkably elaborate and adaptive structures of galls can be due to natural selection acting directly on the plants themselves--seeing that the adaptation has reference to the needs of their parasites--it is quite possible that the phenomena may be due to natural selection acting indirectly on the plants, by always preserving those individual insects (and larvae) the character of whose secretions is such as will best induce the particular shapes of galls that are required. Several other correspondents took part in the discussion, and most of them accepted the above explanation. Mr. T. D. A. Cockerell, however, advanced another and very ingenious hypothesis, showing that there is certainly one conceivable way in which natural selection might have produced all the phenomena of gall-formation by acting directly on the plants themselves[65]. Subsequently Mr. Cockerell published another paper upon the subject, stating his views at greater length. The following is the substance of his theory as there presented:-- [65] _Nature_, vol. xli, p. 344.