Beprodiietion & MuUipliecUion of Diatoms. By Count Castracane. 27 



which occur in quantities in every spring and in every ditch, noting 

 diligently every phenomenon which they present? This is the 

 recommendation which I make to those young observers who, when 

 commencing the study of diatoms, have come to me for advice. Those 

 who accept this advice will very frequently have the opportunity of 

 observing that the endochrome presents different aspects in the same 

 species, being sometimes scanty, and sometimes so abundant as to 

 occupy the whole of the cell-cavity, where it is arranged in imperfect 

 plates or in irregular granules, while sometimes the same species has 

 its endochrome organized in numerous small masses of uniform shape 

 and size. Similar differences are familiar to every one ; but I do not 

 know that any one has at present attempted an explanation of them. 

 Mr. W. Smith himself has indicated it in one of the coloured figures 

 of the frontispiece of the two volumes of the * Synopsis,' more espe- 

 cially in that to vol. ii. ; but I do not know that he refers to it in the 

 text. As long ago as 1873 I ventured an explanation of the 

 phenomenon in the memoir " On the Diatoms of the Coasts of Istria 

 and Dalmatia," published in the Proceedings of the Accademia 

 Pontificia dei nuovi Lincei, xxvi., sittings 5 and 6, where I argued, 

 from the appearance presented by Striatella unipunctata Ag., the 

 central mass of which had a stellate form consisting of a group of 

 numerous distinct fusiform corpuscles, and reaffirmed the view that 

 this condition of the endochrome, as well as the more frequent state 

 which occurs in very many diatoms, of a differentiation into round 

 masses of uniform size, is the prelude to the formation of sporules or 

 gonidia. This view of mine passed unnoticed at the time ; but I am, 

 on my part, continually confirmed in the correctness of this opinion. 



In this state of things it is my most ardent desire and my warmest 

 wish that the Eoyal Microscopical Society of London, which has done 

 so much service to microscopy, both by the impulse it has given 

 to the perfecting of the Microscope, and by having pointed out the 

 best use to make of it, and the great number of its applications, should 

 institute a searching examination of the views I have formulated on 

 the more important biological phenomena of diatoms, these views being 

 entirely the result of my studies and of my observations. A Society 

 so illustrious, and which has among its members naturalists and 

 microscopists of the highest eminence, in taking into consideration 

 this request of mine, will exercise the most weighty influence on the 

 progress of diatomology, which is connected with so many other 

 studies, and in which there are still so many points of controversy. 

 For my own part, far as I am from believing that, after examination 

 and discussion, any of my views will not be proved to be correct, it 

 will nevertheless be to me useful, and therefore pleasant, to assist in 

 the discovery of truth, and to admit the weak side of my explanations, 

 whether in themselves or in the arguments which I have brought 

 forward. 



