I will now show that offspring can be, and not very infrequently is, affected by occurrences that have produced a deep impression on the parent organism--the effect produced on the offspring being such as leaves no doubt that it is to be connected with the impression produced on the parent. Having thus established the general proposition, I will proceed to the more particular one--that habits, involving use and disuse of special organs, with the modifications of structure thereby engendered, produce also an effect upon offspring, which, though seldom perceptible as regards structure in a single, or even in several generations, is nevertheless capable of being accumulated in successive generations till it amounts to specific and generic difference. I have found the first point as much as I can treat within the limits of this present article, and will avail myself of the hospitality of the _Universal Review_ next month to deal with the second. The proposition which I have to defend is one which no one till recently would have questioned, and even now, those who look most askance at it do not venture to dispute it unreservedly; they every now and then admit it as conceivable, and even in some cases probable; nevertheless they seek to minimise it, and to make out that there is little or no connection between the great mass of the cells of which the body is composed, and those cells that are alone capable of reproducing the entire organism. The tendency is to assign to these last a life of their own, apart from, and unconnected with that of the other cells of the body, and to cheapen all evidence that tends to prove any response on their part to the past history of the individual, and hence ultimately of the race. Professor Weismann is the foremost exponent of those who take this line. He has naturally been welcomed by English Charles-Darwinians; for if his view can be sustained, then it can be contended that use and disuse produce no transmissible effect, and the ground is cut from under Lamarck's feet; if, on the other hand, his view is unfounded, the Lamarckian reaction, already strong, will gain still further strength. The issue, therefore, is important, and is being fiercely contested by those who have invested their all of reputation for discernment in Charles-Darwinian securities. Professor Weismann's theory is, that at every new birth a part of the substance which proceeds from parents and which goes to form the new embryo is not used up in forming the new animal, but remains apart to generate the germ-cells--or perhaps I should say "germ-plasm"--which the new animal itself will in due course issue.