ON BIOLOGICAL ANALOGIES. 275 



Mr. Romanes, in his volume on " Animal Intelligence," elaims 

 for the lowest forms some amount of intelligence.* If true of the 

 Amoeba and of Infusoria, like phenomena being exhibited in certain 

 Alga?, may it not be true of them also ? 



The only remaining aspect of this subject to which I will now 

 briefly allude is the analogy between the diseases of plants and 

 animals. The importance, as well as the usefulness, of studying 

 the manifestations of disease in both kingdoms was strongly urged 

 by Sir James Paget in his address at the British Medical Associa- 

 tion in 1880. f It is not my intention to follow him through this 

 Address, which abounds with useful and apposite suggestions, but to 

 pick up a paragraph or two here and there to exhibit its features. " I 

 have long and often felt," he says, " that we might gain help from 

 studying the consequences of injury and disease in the structures of 

 plants ; " and again : " I have seen enough to make me more than 

 ever sure that human pathologists may find, in watching the con- 

 sequences of injuries and diseases of plants, facts of the highest 

 interest in their more proper study." 



And first of hypertrophy. " There are in plants," he says, 

 " abundant opportunities of studying those forms of hypertrophy 

 which depend on an increased supply of nutritive material to any 

 part. To mention but one : the arts of partial or complete 

 ' ringing ' and of constricting or bending the branches of trees 

 depend for success on their insuring an accumulation of nutritive 

 sap in the part of the branch from which its movement is checked. 

 The result is what we may call an hypertrophy of flowers, or, in 

 other instances, of fruit, or wood, or bark, proportionate to the 

 increased supply of nutriment, just as, in ourselves, hairs and 

 some other structures will grow excessively with an excessive 

 efflux of blood ; or, still more, and in almost exact parallel, as 

 limbs will grow with a retarded reflux of lymph." He then pro- 

 ceeds to illustrate compensatory hypertrophy with some examples, 



* " No one can have watched the movements of certain infusoria without 

 feeling it difficult to believe that these little animals are not actuated by 

 some amount of intelligence. Even if the manner in which they avoid 

 collisions be attributed entirely to repulsions set up in the currents which 

 by their movements they create, any such mechanical explanation certainly 

 cannot apply to the small creatures seeking one another for the purposes of 

 prey, reproduction, or, as it sometimes seems, of mere sport." — " Komanes, 

 Animal Intelligence.'' 



t "An Address on Elemental Pathology," by Sir James Paget. — "British 

 Medical Journal," Oct. 16 and 23, 1880. 



