2io /. ARTHUR THOMSON [march 



that an Arab mare which had borne a hybrid to a quagga, had subse- 

 quently colts by a horse, and that these were marked by stripes and 

 by some other peculiarities supposed to be quagga-like. Agassiz, 

 Darwin, Spencer, and others have expressed their belief in the fact ; 

 Settegast, Nathusius, Weismann, and others are extremely sceptical ; 

 Professor Ewart has followed the path which Romanes had only 

 time to set foot upon, the only secure path, that of definite 

 experiment. 



In general terms, he has made a number of experiments likely to 

 give telegony the best possible chance of declaring itself, and although 

 he displays his scientific mood in abstaining from dogmatic conclusion, 

 and in suggesting fifteen other experiments which should be made, 

 the verdict is that so far the evidence of any undoubted telegony 

 is most unsatisfactory. The experiments prove this at least, that 

 telegony does not always occur, indeed that anything suggestive of it 

 occurs only in a very small percentage of cases. Moreover, where 

 peculiar phenomena of inheritance were observed, they seemed to be 

 readily explicable by the reversion hypothesis. It is impossible to 

 withhold admiration when we consider these experiments, involving as 

 they have done so much patience and vigilance, hindered as they 

 have often been by mortality, and very costly withal. If Professor 

 Ewart had originally any bias on the matter, there is no trace of this 

 in his experimentation and exposition. 



The most general form of the belief in telegony may be called the 

 infection hypothesis, the idea of which is that the reproductive organs 

 of the mother are specifically infected by having offspring to a 

 particular male, — so specifically infected that her subsequent offspring by 

 other males may exhibit some characteristics of the first sire. The race- 

 horse Blair Athol had a very characteristic blaze, or white bald face ; 

 it is said that mares after having foals to Blair Athol, produced Blair 

 Athol-like foals to other stallions utterly unlike Blair Athol. It is 

 supposed that this resemblance was due to an infection of the germinal 

 material by the Blair Athol semen. 



A slightly modified form of the infection hypothesis is that of 

 saturation, according to which it is supposed that the characters of the 

 sire expressing themselves in the unborn embryo saturate into the 

 dam, and affect her constitution in such a way that her offspring by 

 subsequent sires inherit some of the characteristics of the first. But 

 while it is conceivable that this may sometimes be the case with a 

 poison or a protective toxin which might diffuse in and out, it seems 

 almost inconceivable when we think of structural characters. We can 

 imagine that a sire infected with some virulent disease, and showing 

 certain structural disturbances associated therewith, may have offspring 

 which are similarly affected, and that the influence from them unborn 

 may saturate into the mother and affect her, so that subsequent 

 offspring by a healthy sire are modified after the manner of the first. 



