RECENT OBSERVATIONS ON THE GONIDJA QUESTION. 135 



ttient of tne spores was used up, the germinating filaments 

 ■would still be able to continue growing for some time, with- 

 out addition of inorganic food, but simply at the cost of the 

 organic food from the algse. Should, then, the branches of the 

 germinating filaments probably be more delicate than the 

 hyphfc from the perfect lichen- thallus, it might be possible 

 to observe distinctly the first result of the contact of the 

 germinating filaments and the algae. 



After I had gone through the course of my first culture 

 it at once suggested itself to me that the impurity of the Cys- 

 tococcus masses must operate peculiarly unfavorably on the 

 success of my experiment. 



Indeed, upon gathering small quantities of the algae for 

 my cultures, it always appeared, upon looking them over, 

 that they were contaminated by hyphse of minute fungi, fre- 

 quently by protonemata, but, above all, by other algse. To 

 obviate this I determined to employ the /ree/y -growing Cys- 

 tococcus no more, but only that which I had disengaged from 

 the lichen-thallus ; this, indeed, I could do without in the 

 least diminishing the results to be obtained, since, indeed, 

 the most violent opjDonents of Schwendener's theory acknow- 

 ledge the perfect agreement of the gonidia of most hetero- 

 merous lichens with Cystococcus humicola, and in this 

 very agreement find a reason, indeed, to remove Cysto- 

 coccus humicola from the algoe. We find von Krempel- 

 huber, for instance, saying, " Den Nachweis jener Aehnlich- 

 keit gewisser Flechtengonidien mit gewissen niederen 

 Algen, oder meinetwegen Identitcit,'^ &c. 



One great difficulty being obviated, there still appeared 

 a much greater and more troublesome one, namely, mould-for- 

 mation. In the first period of my research (February to 

 December, 1872) I found, I might say invariably, moulds on 

 the substratum. Of course, the growth of the algae and 

 germinating filaments Avas in consequence very much 

 interfered with or usually wholly stopped. 1 tried, in 

 the following ways, to get rid of these troublesome 

 enemies. 



1. By means of carbolic acid, of Avhich a drop was added 

 to the water in the vessel intended to receive the slides, or a 

 wad moistened with it was placed in the damp space in the 

 bell glass. In this manner I succeeded, in some cases, in 

 preventing the formation of mould during the culture ; still 

 this was constantly coupled with non-germination of the 

 lichen-spores, and with a total loss of colour and contraction 

 of the contents of the alga?. The cure was worse than the 

 disease. By employing extremely little carbolic acid the 



