98 SUMMAEY OF CURRENT RESEARCHES RELATING TO 



like fungi, and they endure for ages unaffected by frost or snow, whereas 

 fungi are short-lived and disappear on the first approach of frost. 

 Lichens have many chemical elements in their composition unknown to 

 fungi, such as colouring matters, various acids, and lichenin. The 

 hyphaa and paraphyses of the latter are thin-walled, non-elastic, non- 

 amylaceous, and dissolve in hydrate of potash ; while those of lichens 

 are thicker-walled, more flexible, and do not dissolve in hydrate of 

 potash. A difference is also manifested in the spores of lichens ; they 

 are smoother, capable of greater endurance, their walls are thicker, more 

 mucose and pellucid than those of fungi. 



The development of sporids in the asci is traced and illustrated, 

 but Stahl's theory of the origin of the apothece in a fertilized ascogone 

 was doubted. The apothece may begin in an act of fertilization by the 

 " spermatia " (pollinoids), while much mystery still hangs about the 

 process of lichen-fertilization, yet present knowledge, as far as it goes, 

 favours the idea that such fertilization takes place in the substance out 

 of which the spores are formed rather than by direct contact between 

 the " spermatia " and the spores themselves, and the impregnated mass 

 could only take place at the origin of the apothece, or at some initiatory 

 stage, as the spores and asci are developed within it ; but that the 

 apothece springs from a fertilized ascogone is not proved. It seems 

 rather to begin in the fruitful centre, by the hypha becoming denser, and 

 then differentiating into the cellular hypothece or bed, from which arise 

 the whole contents of the hypothece. 



Lichen spores originate in the hyaline protoplasmic contents of the 

 ascus or theca, which become more grumous as the parent-cell advances. 

 Through the pellucid walls of the theca denser spots begin to show, 

 casting a slight shadow, as may be seen in the young asci of Pertusaria 

 fallax, PJiyscia ciliaris, &c. These denser spots are the spores taking 

 shape, and they gradually show a thin coating and distinct form. The 

 spore is a double-walled cell of varying size and shape, simple or 

 septate. 



How the colour of lichen-spores is taken up, or whence it is 

 secreted, is a mystery ; but there is the fact, in many lichens, of a hyaline 

 or colourless closed theca or spore-sac, full of blackish-brown or reddish- 

 brown spores. The coloured pigment of the spores is lodged, not in the 

 contents, but in the epispore or outer wall. When spores of PJiyscia 

 pulverulenta are broken up, every separate particle retains the same dark 

 colour as when the spore is entire. 



Saccharomyces apiculatus.* — Herr C. Amthor concludes, from the 

 different composition of the same wine fermented by different cells of 

 this ferment, that there must be distinct varieties of the yeast. The 

 total amount oi acid formed during fermentation is about three times 

 greater than that found by Pasteur with ordinary yeast. In beer-wort, 

 S. apiculatus caused, in 30 days, the formation of only 0'93 per cent, of 

 alcohol. The author believes that this species does not ferment maltose, 

 and that this property furnishes us with a means, not only of detecting 

 small quantities of dextrose in the presence of maltose, but of estimating 

 the quantity present by the amount of alcohol formed. 



* Zeitschr. Phys. Chem.. xii. (1888) pp. 558-64. See Journ, Oliem. Soc, 1888 

 (Abstr.), p. 1218. 



