THE ORIGIN OF MORALITY 57 



consequence, " kingly " or " majestic " the organism becomes, 

 the more susceptible it is to infection and disease. 



The " huge " and " majestic " sunfish, Orthagoriscus mola, 

 for instance, is a veritable hotbed of infection. There are, 

 according to Geddes and Thomson, the tuft of barnacles upon 

 his back, the biting isopods like enormous fleas upon his skin, 

 the trematodes sucking like leeches upon his eyes ; and within 

 we find 



not only his alimentary canal crammed with worms more than with food, 

 and his liver changed from its natural brown almost into the likeness of a 

 tangle of white worsted, of which each thread is a tape-worm. 



We are told that " neither frog nor lizard, serpent nor bird 

 escapes " infection and disease. More and more it is seen that 

 disease has largely a biological origin, i.e., that it is due to some 

 perverted biological relatedness. All of which points to the 

 explanation here adduced that the origin of disease is to be found 

 in a divorce from an erstwhile symbiotic relationship. The 

 parasites infecting the sunfish, or for that matter all parasites, 

 are liable in turn to still more malignant infections, presenting 

 many gruesome phenomena of Hyper-parasitism. Such vicious 

 circles of infection and disease are more frequently met with every 

 day. I have contended these ten years that there is a biological 

 causation of disease and that disease is the most general cause of 

 extinction. I am glad to find this view is borne out by further 

 facts inasmuch as evidence has quite recently been accumulating 

 that infection and disease have been widespread certainly in the 

 early vertebrate periods, with a strong probability that in many 

 cases disease has been the cause of extinction. There has also 

 been a widely felt need among Pathologists for a definition of 

 health in terms of resistance to disease. Here, too, I feel sure 

 the recognition that health pre-eminently depends upon symbiotic 

 support will prove of immense help. 



Let us here consider another striking example supporting 

 the important proposition that biological conduct which avails 

 not towards life, renders the organism both weaker and malignant 

 and therefore liable to clashes with the interests of truly viable 

 organisms. Few would have imagined that the case of hay- 

 fever provides an illustration of the biological causation of 

 disease, and, more particularly, of the truth that even comparative 

 improvidence on the part of some organisms contains elements 

 of danger and of disease to others more strenuously inclined. 



