ii6 Darwin, and after Darwin. 



I have not succeeded in corroborating these results. 

 It must be added, however, that up to the time of 

 going to press my experiments on this, the easiest 

 branch of the research, have been too few fairly to 

 prove a negative. 



5th. Exophthalmia in animals born of parents in which an 

 injury to the restiform body had produced that protrusion of the 

 eyeball. ... In these animals, modified by heredity, the two 

 eyes generally protruded, although in the parents usually only 

 one showed exophthalmia, the lesion having been made in most 

 cases only on one of the corpora restiformia. 



I have fully corroborated the statement that 

 injury to a particular spot of the restiform body is 

 quickly followed by a marked protrusion of the eye- 

 ball on the same side. I have also had many cases 

 in which some of the progeny of parents thus affected 

 have shown considerable protrusion of the eyeballs on 

 both sides, and this seemingly abnormal protrusion 

 has been occasionally transmitted to the next gener- 

 ation. Nevertheless, I am far from satisfied that 

 this latter fact is anything more than an accidental 

 coincidence. For I have never seen the so-called ex- 

 ophthalmia of progeny exhibited in so high a degree 

 as it occurs in the parents as an immediate result 

 of the operation, while, on examining any large 

 stock of normal guinea-pigs, there is found a con- 

 siderable amount of individual variation in regard 

 to prominence of eyeballs. Therefore, while not 

 denying that the obviously abnormal amount of 

 protrusion due to the operation may be inherited 

 in lesser degrees, and thus may be the cause of the 

 unusual degree of prominence which is sometimes 

 seen in the eyeballs of progeny born of exophthalmic 



