278 



much time over this branch of organic existence should not 

 have been so fortunate as I was in possessing a wise and 

 patient counsellor in the late Dr. Walker-Arnott. I can truly 

 say that had it not been for his invaluable friendly advice, I, 

 too, would have doubtless ranged myself with the manu- 

 factuiers of species and synonym accumulators. Often have 

 the kindly words he has Avritten me made me pause ere I, as 

 he pithily remarked, " rushed into print " with supposed dis- 

 coveries, which I wou.ld have been ashamed of thereafter. 

 Dr. Arnott says " a microscopist looks on everything as sub- 

 servient to the microscope, and that whatever he sees, and which 

 appears distinct to the eye, he thinks ought to be described or 

 figured as distinct. I am, on the other hand, a naturalist, a 

 botanist in particular, and use the microscope, simple or 

 compound, as a necessary evil, merely to enable my eyes to 

 see better minute structures, but whether these differences 

 amount to specific or generic importance, or are only peculiar 

 ibrms of one species, is the result of analogy, a mental process 

 which can only be attained by a training in botany in all its 

 branches, for many years." Natural objects, like the Diato- 

 macese, which can only be seen after they are magnified 

 several thousand times, and then only under peculiar circum- 

 stances of illumination, must be difficult of comprehension, 

 even if their life history were much more simple and more 

 easily studied than it is. I cannot too strongly caution the 

 intending student of this enticing branch against trusting to a 

 few and hasty observations made upon the dead skeleton of 

 the jjlant. It is only Avlien they are studied in the living state 

 that the Diatomaceoe can be understood, and even then only 

 with difficulty. 



But one more abstract from my note-book and I must draw 

 these remarks to a close. In the early part of November, 

 1868, I made a collection of Colletonema vulgare, and for 

 some time have been able to keeji^it alive in a bottle so as to 

 study its peculiarities. And here let me say that many 

 minute forms of both animal and vegetable life which I have 

 been unable to rear otherwise, I have found to flourish in 

 phials with small necks, or those with large ones, which have 

 the aperture partly stopped with a loose cover of some kind. 

 It would seem that the gases given off from the human body, 

 and accumulating in dAvelling rooms, in which 1 have kept 

 specimens, are deleterious to these small forms, and the 

 partial closing of the vessel prevents, to a great extent, their 

 entrance. My specimens of Colletonema flourished finely and 

 grew considerably. I have been thus enabled to watch 

 them, as I may say, building their tubes; this species, con- 



