400 



deposition is periodical. At first I thought tliat in tliis periodicity 

 light is concerned, hut tiie formation of rings also occurs in llu; 

 dark, so that they seem to be of the same nature as the rings ot 

 LiESEGANG, which, for exam[)le, are formed when siKernitrate diffuses 

 in plares of chromate gelatin, wherein the silverchromate precipitates 

 in rings, separated by rings without siKerchromate. 



As to the way in which the nianganicompound originates from 

 the inanganocarbonate, it appears that this may take place as well 

 within as without the mycelium. That this can indeed occur in the 

 cells 01- at least in the cell-walls, is shown by the great accumulation 

 in the wall, and this is quite in accordance with the character of 

 nutrient substance of the cai-bonate, referred to al)o\e. The increase 

 of the sferites, however, takes place in a way suggesting the idea that 

 also to a fairly great distance from the mvcelium an oxidising agent 

 is spread, able to transmit the oxygen of the air to the carbonate. 

 I infer this from the fact that the formation of sferites often occurs 

 in the midst of manganocarbonate plates, which remain snow-white 

 in the vicinity, and 1 snppose that if the blackish brown oxide 

 originated from the rather far distant mycelium, the way between 

 should be coloured brown by a solution of that oxide. It must, 

 however, be noted that such a bi-own-colouring of the white 

 culture medium is obserxed in other cases, as with Sporoct/be 

 chartoikooii, and furthermore that 1 have not been able to oxidise 

 manganocarbonate by means of oxidase and peroxidase of different 

 origin, of which we should first of all think as causing the said 

 distance-reaction. That peroxidase could not be concerned was to 

 be expected, ns for its action hydrogenperoxide must be present, 

 which directly reduces the nianganicompound. But that this oxida- 

 tion could neither be enacted by oxidase was not to be foreseen. 



In this relation I wish moreover to remark that the mangano- 

 carbonate is kept by me as a diluted pap in stoppered bottles under 

 water, in order always to have it ready foi' experiments. It then 

 remains white for years without any precaution, whilst likewise 

 my manganocarbonate agarplates continue unchanged for months, 

 nay, ever, for more than a year, at free accession of air. Hence 

 the statement met with in some manuals for chemistry, that this 

 substance oxidises already at the air, requires a nearer explanation 

 of the circumstances accompanying this change, for example strong 

 drying over a Bunsen flame, or presence of alkaline vapours. 



To the organic substances that can oxidise manganocarbonate, 

 chinou belongs. Formation of sferites I haxe not observed, and 

 there is not the least reason to accept that the described moulds 



