10 EEPOET — 1894. 



striking but more obvious instance still is Life — animal and vegetable 

 Life — the action of an unknown force on ordinary matter. What is the 

 mysterious impulse which is able to strike across the ordinary laws of 

 matter, and twist them for a moment from their path ? Some people 

 demur to the use of the term ' vital force ' to designate this impulse. In 

 their view the existence of such a force is negatived by the fact that 

 chemists have been able by cunning substitutions to produce artificially 

 the peculiar compounds which in nature are only found in organisms that 

 are or have been living. These compounds are produced by some living 

 organism in the performance of the ordered series of functions proper to 

 its brief career. To counterfeit them — as has been done in numerous 

 cases — does not enable us to do what the vital force alone can effect — to 

 bring the organism itself into existence, and to cause it to run its appointed 

 course of change. This is the unknown force which continues to defy not only 

 our imitation but our scrutiny. Biology has been exceptionally active and 

 successful during the last half-century. Its triumphs have been brilliant, 

 and they have been rich enough not only in immediate result but in the 

 promise of future advance. Yet they give at present no hope of penetrat- 

 ing the great central mystery. The progress which has been made in the 

 study of microscopic life has been very striking, whether or not the results 

 which are at present inferred from it can be taken as conclusive. Infini- 

 tesimal bodies found upon the roots of plants have the proud office of 

 capturing and taming for us the free nitrogen of the air, which, if we are 

 to live at all, we must consume and assimilate, and yet which, without 

 the help of our microscopic ally, we could not draw for any useful purpose 

 from the ocean of nitrogen in which we live. Microscopic bodies are 

 convicted of causing many of the worst diseases to which flesh is heir, 

 and the guilt of many more will probably be brought home to them in due 

 time ; and they exercise a scarcely less sinister or less potent influence on 

 our race by the plagues with which they destroy some of the most valuable 

 fruits of husbandry, such as the potato, the mulberry, and the vine. 

 Almost all their power resides in the capacity of propagating their kind 

 with infinite rapidity, and up to this time science has been moi'e skilful in 

 describing their ravages than in devising means to hiiider them. It would 

 be ungrateful not to mention two brilliant exceptions to this criticism. 

 The antiseptic surgery which we owe chiefly to Lister ; and the inocula- 

 tion against anthrax, hydrophobia, and perhaps some other diseases, 

 which we owe to Pasteur, must be recorded as splendid victories over the 

 countless legions of our infinitesimal foes. Results like these are the great 

 glory of the scientific workers of the past century. Men may, perhaps, 

 have overrated the jarogress of nineteenth-century research in opening 

 the secrets of nature ; but it is difficult to overrate the brilliant service it 

 has rendered in ministering to the comforts and diminishing the sufferings 

 of mankind. 



If we are not able to see far into the causes and origin of life in our 

 own day, it is not probable that we shall deal more successfully with the 



