PREFACE. 13 



still. Suppose that lie extended his researches some- 

 what to those minuter vegetable forms, the mosses, 

 fungi, lichens ; suppose that he went a little further 

 still, and tried what the microscope would show him 

 in any stagnant pool, whether fresh water or salt, of 

 Desmidiae, Diatoms, and all those wondrous atomies 

 which seem as yet to defy our classification into plants 

 or animals. Suppose he learnt something of this, but 

 nothing of aught else. Would he have gained no 

 solid wisdom ? He would be a stupider man than I 

 have a right to believe any of my readers to be, if he 

 had not gained thereby somewhat of the most valuable 

 of treasures namely, that inductive habit of mind, 

 that power of judging fairly of facts, without which 

 no good or lasting work will be done, whether in 

 physical science, in social science, in politics, in 

 philosophy, in philology, or in history. 



But more : let me urge you to study Natural 

 Science, on grounds which may be to you new and 

 unexpected on social, I had almost said on political, 

 grounds. 



We all know, and I trust we all love, the names of 

 Liberty, Equality, and Brotherhood. We feel, I trust, 

 that these words are too beautiful not to represent 

 true and just ideas ; and that therefore they will come 

 true, and be fulfilled, somewhen, somewhere, somehow. 

 It may be in a shape very different from that which 

 you, or I, or any man expects ; but still they will be 

 fulfilled. 



But if they are to come true, it is we, the individual 

 men, who must help them to come true for the whole 

 world, by practising them ourselves, when and where 

 we can. And I tell you that in becoming scientific 

 men, in studying science and acquiring the scientific 



