278 M. Otto Hahn on Eozoon canadense.^ 



chambers, the passages, and the " film " of the " giant Fora- 

 minifer " originated from olivine crystals ; therefore they are 

 pure mineral structures. 



I have observed the same things even in the Canadian 

 rock ; only in it the olivines are not so fresh as in the former. 

 But as the serpentine mass occurs in exactly the same form 

 as there on the outer surface of the hand-specimen, the con- 

 clusion that both were originally in the same state, is per- 

 fectly justifiable. 



The calcareous layers occur in serpentine rocks which 

 certainly contain no Eozoon-'A\YWc\\\re. There is nothing in 

 favour of their owing their origin to a Foraminiferous test. 



The question will now be raised, Do the canal-systems of 

 the Canadian rock also exist in the two hand-specimens? 

 No ; with the exception of one spot in a green mass which 

 does not polarize. It might, however, possibly be that the 

 mass of limestone was over- or underlying, and that the canal- 

 system occurred in the limestone. But this very spot also 

 exhibits the clear points (disseminated arragonite), with which, 

 according to my observations, the presence of the canal-system 

 is always associated, even in the Canadian rock. In all the 

 rest of the rock, in the thin sections, there is no arragonite 

 and no canal-system. 



Let us now draw the direct conclusions : — 



During the separation of the arragonite from the limestone, 

 water, or some other fluid containing lime, remained behind. 

 By existing pressure tliis penetrated into the soft limestone 

 mass in exactly the same way that every fluid penetrates into 

 another, denser one, in ramifications. 



This may be regarded as hypothesis, although the expla- 

 nation is not far-fetched. It may be objected that this pro- 

 cess must also occur elsewhere. 



But I have further been able to demonstrate these canal- 

 systems in the gneiss of Mont Blanc and the Schwarzwald — 

 nay, even in the syenite of the Plauenscher Grunde (Saxony) 

 and in the syenite of the Schwarzwald. I have observed 

 them in about thirty tliin sections of these under crossed Nicols. 

 It is only thus that they make their appearance in the trans- 

 parent felspar and limestone, but then as beautifully as in the 

 Canadian specimens. 



Thus from this side also, by the demonstration of a per- 

 fectly similar phenomenon in other rock, we obtain an expla- 

 nation of the canal-systems. 



And thus the last character of the " giant Foraminifer " is 

 got rid of — a character, however, which could not alone furnish 

 the proof of the organic nature of the ^0^00/2 -structures. 



