The same objection holds true of the recent experiments, in which the germ cells have been modified by modifying the interior medium or internal environment by means of antibodies and hormones. No one doubts the possibility of influencing heredity by a direct modification of the germ cells, especially when, as is always the case in these experiments, the modification produced is destructive rather than constructive. The experiments, therefore, of Prof. M. F. Guyer of Wisconsin University, in which a germinally-transmitted eye defect was produced by injecting pregnant female rabbits with an antilens serum derived from fowls immunized to the crystalline lens of rabbits as antigen, are beside the mark. To demonstrate the Lamarckian thesis one must furnish evidence of a constructive addition to inheritance by means of prior somatic acquisition. The transmission of defects artificially produced is not so much a process of inheritance (transmission of type) as rather one of degeneracy (failure to equate the parental type).[1] Commenting on Guyer’s suggestion that an organism capable of producing antibodies that are germinally-destructive, may also be able to produce constructive bodies, Prof. Edwin S. Goodrich says: “The real weakness of the theory is that it does not escape from the fundamental objections we have already put forward as fatal to Lamarckism. If an effect has been produced, either the supposed constructive substance was present from the first, as an ordinary internal environmental condition necessary for the normal development of the character, or it must have been introduced from without by the application of a new stimulus. The same objection does not apply to the destructive effect. No one doubts that if a factor could be destroyed by a hot needle or picked out with a fine forceps the effect of the operation would persist throughout subsequent generations.” (_Science_, Dec. 2, 1921, p. 535.) [1] A good definition of degeneracy is that of A. F. Tredgold, who says: “I venture to define degeneracy as ‘a retrograde condition of the individual resulting from a pathological variation of the germ cell.’” (Smithson. Inst. Rpt. for 1918, p. 548.)