168 Dr. Wallich on the Origin of the 



excessive shrinkage which colloid silica undergoes in passing 

 from the pectous to the solid state ; and certainly, to one who 

 has experimented with colloid silica, the wonder on Dr. Wal- 

 lich 's hypothesis would be, not that the flints sliow signs of 

 shrinkage, but that they do not present them more markedly. 

 The time for conclusions based on superficial resemblances is 

 now gone by ; we no longer regard ' dendrites ' as fossils on 

 account of their moss-like form, nor profess to be ' able to tell 

 an honest man by the smell ' " (Mr. Sollas's paper, p. 459). 



This extraordinary composition may, or may not, have been 

 written in a wholly serious spirit. It has appeared, however, 

 in a journal occupying a foremost rank in the scientific 

 literature of our time, and is therefore calculated to engender 

 an idea that it embodies a legitimate criticism upon views cor- 

 rectly ascribed to me. This is, in itself, a more than sufficient 

 reason why it should be seriously answered, and why some 

 other personal observations made by Mr. Sollas in the same 

 journal, in regard to my writings, should receive distinct refu- 

 tation at my hands. 



Since Mr. Sollas has become so zealous an advocate for 

 preciseness of expression on the part of a non-professional 

 naturalist as to take exception at the use of the word amoehi- 

 form — which he alleges, but incorrectly, was " repeatedly " 

 employed in my paper, — how comes it, I would ask, that, in 

 the very same paragraph that contains his criticism, he should 

 himself have described, in language of his own selection, and, 

 it is to be assumed, conforming in all respects with his en- 

 lightened views, "the irregular and fantastic FLOWING outlines 

 of the flint-nodules " as being " responsible for much of the 

 theorizing" he refers to; my name being pointedly associated 

 with this observation? And how comes it that, in the 

 'Annals' for December last (p. 38), he should, when speak- 

 ing of the FORM of these nodules, have thus expressed 

 himself : — " In form they vary greatly, some being flabellate, 

 some irregularly conical, others consist of a somewhat ellip- 

 soidal body on a short stalk, while many are irregular and 

 amorphous"? 



The word amcebiform, though a hybrid and but little re- 

 moved from the Latin and Greek jargon which day by day 

 threatens to drive plain English out of our scientific termino- 

 logy, is undoubtedly expressive of the unique kind of outline 

 and nodulation I desired to picture. There is no English 

 equivalent for Amceha, and consequently none for amcebiform. 

 Hence no other word could have adequately conveyed my 

 meaning. It was accordingly used by me ; and I stand by it. 



