[184] Lamarck's division of _Animaux sensibles_ comprises the insects, arachnids, crustacea, annelids, cirrhipedes, and molluscs. [185] Rather a strange view to take, as the brain of insects is now known to be nearly as complex as that of mammals. [186] Richerand, _Physiologie_. vol ii. p. 151. [187] "As all animals do not have the power of performing voluntary acts, so in like manner _instinct_ is not common to all animals: for those lacking the nervous system also want the organic sense, and can perform no instinctive acts. "These imperfect animals are entirely passive, they do nothing of themselves, they have no wants, and nature as regards them treats them as she does plants. But as they are irritable in their parts, the means which nature employs to maintain their existence enables them to execute movements which we call actions." It thus appears that Lamarck practically regards the lowest animals as automata, but we must remember that the line he draws between animals with and without a nervous system is an artificial one, as some of the forms which he supposed to be destitute of a nervous system are now known to possess one. [188] It should be noticed that Lamarck does not absolutely state that there are no variations whatever in instinct. His words are much less positive: "_Sans offrer de variation notable._" This dues not exclude the fact, discovered since his time, that instincts are more or less variable, thus affording grounds for Darwin's theory of the origin of new kinds of instincts from the "accidental variation of instincts." Professor James' otherwise excellent version of Lamarck's view is inexact and misleading when he makes Lamarck say that instincts are "perpetuated _without variation_ from one generation to another, so long as the outward conditions of existence remain the same" (_The Principles of Psychology_, vol. ii., p. 678, 1890). He leaves out the word notable. The italics are ours. Farther on (p. 337), it will be seen that Lamarck acknowledges that in birds and mammals instinct is variable. [189] It is interesting to compare with this Darwin's theory of the origin of the same animals, the flying squirrels and Galeopithecus (_Origin of Species_, 5th edition, New York, pp. 173-174), and see how he invokes the Lamarckian factors of change of "climate and vegetation" and "changing conditions of life," to originate the variations before natural selection can act. His account is a mixture of Lamarckism with the added Darwinian factors of competition and natural selection. We agree with this view, that the change in environment and competition sets the ball in motion, the work being finished by the selective process. The act of springing and the first attempts at flying also involve strong emotions and mental efforts, and it can hardly be denied that these Lamarckian factors came into continual play during the process of evolution of these flying creatures.