126 Transactions of the Royal Microscopical Soeiety. 



really did not care two pins ; and I certainly did expect a different 

 answer; for though it is impossible not to admire the amazing 

 dexterity with which his has been put together, it is equally im- 

 possible not to perceive that its object is rather victory than any search 

 after truth, and that scientific truth is an object quite secondary to 

 his desire to bar the way against fresh evidence by the antecedent 

 prejudice of " diffraction phenomena," 



It is indeed a clever paper, but its cleverness is in its attorney- 

 ship ; and its only effect will be to lay him open to the reproach, 

 that his reputation for infallibility is dearer to him than the truth. 

 And now, as all here have probably examined Dr. Woodward's 

 photographs by this time, if any of you will take upon you to declare 

 that they represent to you the veritable Frusfulia Saxonica, as it 

 is known in Germany, I will say no more. 



For my own part, the more I look at them, the more I am 

 puzzled to make out for what purpose they were made or sent. 



Only on two of them, — those marked with the letters A and F, — 

 can I discern any resemblance. 



As for the others, — those marked with the letters B, C, J), 

 and E, — they may represent anything, or nothing. 



And here, a propos to their very i^eculiar colour, I would remark 

 that, if we, purely for argumenf s sake, take them as Frustulias, 

 we shall find ourselves in something like a dilemma ; for those who 

 are in the habit of working on FrustuUa Saxonica know well that, 

 of the whole number of frustules on a slide, more than two-thirds are 

 usually of a rusty brown colour, while the rest are of a clear French 

 white ; and that it is only the latter which are capable of being 

 resolved. The rusty ones they may as well let alone. 



They will also notice that, if they happen to focus too deeply, 

 or to set the adjustment-screw far wrong, the result will be to 

 convert the previous clear French white colour of the shell they 

 are looking at into the dingy rusty colour which is natural to the 

 irresoluble ones. 



So that, if, as I said before, we imagine for the nonce his to be 

 Frustulias, we are driven to the conclusion that, either (1) he does 

 not know what frustules he ought to try at, or (2) that his photo- 

 graphs have all been made with the objective out of focus. 

 I myself adopt the first. 



We need not here discuss the goodness or badness of his slides : 

 his fault has been that he mistook one slide for another. 



One gentleman has gone at once to the root of the matter 

 by asking, " But what is FrustuUa Saxonica ? " As some help 

 towards solving this riddle, I have brought with me two unques- 

 tionable slides of that diatom, which I will ask some of you to put 

 under the microscope and to exhibit for me. A careful examination 

 will show you, on the very same slide, some specimens even longer 



