heredity to his offspring. This is entirely contrary to the idea of heredity which is held by nearly everybody. Just a little over one hundred years ago a Frenchman by the name of Lamarck published writings in which he argued very strongly in favor of the inheritance of “acquired characters,” meaning by this that the achievements of parents could be and were transmitted to the offspring. It is evident that this would be a very great advantage; the progress of the race would be secure if the children could inherit directly the achievements of their parents. Of course, it might work the other way around and children might inherit unfavorable acquisitions of their parents as well as favorable. Since the time of Lamarck there has been not only hot discussion of his ideas but also a vast amount of experimentation to find out whether acquired characters actually can be inherited. One of the most famous experiments is that of a man who cut off the tails of mice at birth and did this generation after generation in the hope of being able to produce a race of tailless mice; after a great many generations he abandoned the attempt with the conclusion that the artificial removal of tails from parents would not cause the offspring to be born in the tailless condition. More recently similar experiments have been carried out on kinds of animals that have much shorter lives and in which the generations are correspondingly more frequent. In some cases thousands of generations have been studied without any indication that changes brought about during the lifetime of the parents can be transmitted to the offspring.