( XXX ) 



from a spore which found its way to, and alighted somewhere exter- 

 nally upon, the particular Scytonema or Sirosiphoti ? 



An experimental decision of the " gonidia-question," so far as it 

 relates to these Scytonematous and Sirosiphonaceous forms, is sur- 

 rounded by not a few practical difficulties. A " sowing" of spores 

 upon the algse (as Eeiss did for N'ostoc) in a natural condition could 

 only be carried out by an obseiwer residing in or close to the subalpine 

 situations where these plants dwell, as they could not be cultivated 

 elsewhere. In order to obtain the spores he would fui'ther have, most 

 probably, a troublesome preliminary search ; and, on the other hand, 

 there would hardly be a certainty of the plants selected for inoculation 

 being themselves previously destitute of hyphae or apothecia. Of 

 course, small portions from various places in a tuft of any given alga 

 could be previously well examined, which though if, indeed, found to 

 represent the alga "pure and simple," would not render it absolutely 

 conclusive that some other portion of the tuft might not already have 

 been invaded by the "parasite." However, having selected some 

 plants for experiment, they should be well inoculated with spores, and 

 portions removed from time to time for examination and experiment. 

 If found satisfactory, it would be interesting to try spores from the 

 same and from different species, in order to see the result, and whether 

 the seeming fixity of the foriris and the apparently extreme choiceness 

 of the parasites be true or not, or ultimately whether the theory 

 itself be true or not. "WTiether, for the time being, the truth of the 

 new theory be previously assumed, or its untenability be presupposed 

 would matter very little, if only the suitable opportunity and ready 

 field of operation were at command of the observer. It would seem 

 as if in this way only can either presupposition be justified or nega- 

 tived. 



[This paper will appear in the Proceedings, Series IL, Vol. II. 

 Science, Part 2, Plate 6.] 



Mr. R. C. Tichborne read a Paper entitled "Laboratory Xotes." 



On the Solution of Alloys and Metals hy Acids. 



The object of this note was to point out the advantage of using 

 small shot or spheres of platinum in the place of platinum foil to form a 

 voltaic circuit. The solution is effected in half the time owing to the 

 fact that when the foil touches the particles of metal it becomes 



