424 THE SUPPOSED TRANSMISSION OF MUTILATIONS. 



of acquired changes cannot take place. It would be as unsafe to 

 make this assertion as to state of a ship seen at a great distance, 

 that it is only moving by sails and not by steam simply because the 

 movement appears to be explicable by sails alone. We ought first 

 to attempt to show that the ship does not possess a steam-engine, 

 or at least that the existence of such an engine cannot be proved. 



I believe that I am able to show that the actual existence of the 

 transmission of acquired characters cannot be directly proved ; that 

 there are no direct proofs supporting the Lamarckian principle. 



If we ask for the facts which can be brought forward by the 

 supporters of the theory of the transmission of acquired characters, 

 if we inquire for the observations which induced Darwin, for in- 

 stance, to adopt such an hypothesis, or which at least prevented 

 him from rejecting it, a very brief answer can be given. There are 

 a small number of observations made upon man and the higher 

 animals which seem to prove that injuries or mutilations of the body 

 can, under certain circumstances, be transmitted to the offspring. 



A cow which had accidentally lost its horn, produced a calf with 

 an abnormal horn ; a bull which had accidentally lost its tail, from 

 that time begat tailless calves ; a woman whose thumb had been 

 crushed and malformed in youth, afterwards had a daughter with a 

 malformed thumb, and so on. 



In a great number of such cases every guarantee for the trust- 

 worthiness of the statements is entirely wanting, and, as His and 

 still earlier Kant have already said, they are of no greater value 

 as evidence than the merest tales. But in other cases this asser- 

 tion cannot be made without further examination ; and a small 

 number of such observations can indeed claim a scientific in- 

 vestigation and value. I shall presently discuss this point in 

 greater detail, but I wish now to lay stress upon the fact that, 

 as far as direct evidence goes, we cannot bring forward any 

 proofs in favour of the transmission of acquired characters, 

 except these cases of mutilations. There are no observations which 

 prove the transmission of functional hypertrophy or atrophy, 

 and it is hardly to be expected that we shall obtain such proofs 

 in future, for the cases are not of a kind which lend themselves to 

 an experimental investigation. The hypothesis that acquired cha- 

 racters can be transmitted is therefore only directly supported by 

 the above-mentioned instances of the transmission of mutilations. 



