116 FOOT-NOTES TO EVOLUTION. 
conclusion—they have shown that characters are ac- 
quired, they have usually failed to show that they are 
transmitted to descendants. Among animals one of the 
best-known cases is the inheritance of 
epilepsy and other disorders in guinea- 
pigs, due to certain nervous lesions of 
the parents. But Romanes,* who spent much time in 
trying to corroborate these results, concludes as fol- 
lows: “On the whole, then, as regards Brown-Séquard’s 
experiments, it will be seen that I have not been able to 
furnish any approach to a full corroboration.” 
.Among plants, on the other hand, there is more and 
better experimental evidence, but it is not by any means 
as full or satisfactory as could be wished. Of one thing 
we may be certain—a satisfactory solution of the prob- 
lem can be reached only by experiment, The mere 
observations and inductions of the morphologist, while 
affording valuable collateral evidence, can never furnish 
the crucial test. As long as we deal merely with proba- 
bilities of a low order there will be profound differences 
of opinion—e. g., Cope believes in all the Lamarckian 
factors ; Romanes rejects use and disuse, but believes in 
the others; Weismann rejects all of them. Why? Is 
it because each does not know the facts upon which the 
others build? Certainly not. Those so-called facts are 
merely probabilities of a higher or lower order, and to 
one man they seem more important than to another. 
No conviction based even upon a high degree of proba- 
bility can ever be reached in this way. There is here 
a deadlock of opinion, each challenging the other to 
produce indubitable proof. This can never be furnished 
by observation alone. Possibly even experiment may 
fail in it, but at least it is the only hope. 
Value of direct 
experiment. 
*G.J. Romanes. Post-Darwinian Questions, 1895. 
