108 Capt. G. E. II. Barrett-Hamilton on the 



These miglit, and have, been mistaken for nuptial develop- 

 ment, aesthetic and offensive. They are not so, however, but 

 represent a pathological * condition in which the fish is mani- 

 festly out of condition, and, becoming continually more and 

 nioiv feeble, eventually succumbs . 



AVhat 1 wished to demonstrate was that the coloration 

 and growth are due to a pathological f condition of uncertain 

 nature. I suggested that "it may be a kind of piscine 

 jaundice accompanied by the hypertrophy of certain organs, 

 or it may be (and this I myself believe) that in the effort to 

 produce as much spawn as possible the whole metabolism is 

 so upset that the ordinary excretory organs are unable to do 

 all the work demanded of them, and a last effort is made to 

 get rid of the unduly increased quantity of poisonous products 

 by depositing them in the skin." 



Finally, I drew the conclusion that to such phenomena we 

 may ])Ossibly look for a source and origin of many of the 

 highly developed sexual characters met witli in other animals. 

 In these fish, gaudily coloured and changed in form, but all 

 as the result of pathological conditions, we have several lines 

 of development ready for the operation of sexual selection. 



In tiie above-mentioned paper I had no intention of entering 

 deeply into the work of others, but contented myself with 

 relerring to several important articles. 



To one of these I now wish to refer at greater length, in 



* My friend Dr. F. H. H. Guillemard, one of the Englishmen who 

 have observed and described the phenomena in question (see the ' Cruise 

 of the Marchesa,' vol. i. chapter 6), and to whom I sent a copy of my 

 paper, writes me in a letter of 29th November, 1900, that, although he 

 does not accept my explanation, " there can be no shadow of doubt that 

 the changes in the Hsb are purely pathological." 



.Similarly Dr. Cunningham accepts the pathological condition, although 

 he sees "no general or necessary connection between fecundity, or intense 

 production of milt and eggs, and changes in the body, patliological or 

 otherwise." On the contrary, he " would attribute the changes, the 

 pathological condition, and the death of Oncorhynchus to the excitement 

 and exertion and starvation which accompany the process of spawning" 

 (in lit. of 28th Nov., 1900) — an opinion, after all, not very much ut 

 variance with my own. 



t In the letter quoted above Dr. Cunningham cites the Conger as 

 instance of a tish "which dies after spawning, and which before death 

 shows a pathological condition. I5ut in this ca>e there are in the female 

 no remaritable changes of colour and of structure. The Conger ceases to 

 feed several months before spawning, and when ripe its bones have so 

 much degenerated that they are as soft a.'' cheese and the teeth all drop 

 out. Here there is no excitement or struggle such as occurs among a 

 crowd of salmon struggling with one another and ascending a river for 

 miles from the sea. In the male Conger, which does not grow to more 

 than 2\ feet in length, tlie eyes appear to become larger; but this may 

 be merely due to the shrinking of the tissues of the head."' 



