168 THE ENZYME THEORY OF DISEASE [CH. xi 



other organism, the effect, though not the actual process, of 

 transmutation would be brought about. 



A transference of this kind would present certain diffi- 

 culties. The enzymes if such be their true nature of disease 

 would appear to depend, to some extent, for their activity 

 upon the structure and metabolism of the cell body to which 

 they are attached and if they are to be transferred from one 

 organism to another without loss of function the second host 

 must possess those characters in the way of structure and 

 metabolism which are vital to the activity of the enzymes. 

 This implies certain, and possibly rigid limitations. The pro- 

 blem can best be illustrated by analogy with more familiar 

 things. 



We are able to distinguish at sea, a fleet of fishing smacks, 

 a line of battleships, a couple of pleasure steamers, a solitary 

 four masted barque in full sail. We distinguish these different 

 types of vessels readily from one another by characters analo- 

 gous to the " morphology " of bacteria, that is to say their 

 size, shape, motility and grouping. We have, however, another 

 way of distinguishing them, namely by observing the effects 

 produced by their arrival at a port, analogous to the effects 

 of bacterial " invasion.' 3 The arrival of the fleet of fishing 

 smacks is followed by a rush of people from their houses to 

 the shore (comparable to the exudation of leucocytes), a 

 silvery deposit on the quay-side as they empty their fish, re- 

 placed in a few hours by a brownish membrane as the nets are 

 spread out to dry. The train of " symptoms " is invariable and 

 becomes associated in our minds with the entry into port of 

 this type of vessel. So, too, with the others. The appearance 

 of gunboats may be followed by the destruction of a town 

 (comparable to necrosis). The arrival of the pleasure steamers 

 may be greeted with a display of fireworks (comparable to 

 pyrexia), that of the tall barque with its cargo of spirits may 

 give rise to general intoxication (comparable to delirium). 



Such a sequence, however, is not invariable. For example, 

 the fishing smacks might be employed in smuggling and land 

 a cargo of spirits, giving rise to intoxication on shore. The 

 gunboats might be employed by Royalty on a pleasure cruise 



