CHAPTER VI. — PHENOMENA OF GERMINATION. 347 



The behaviour of Saccharomyces Cerevisiae, though not strictly belonging to 

 this connection, may be adduced to show that Fungus-spores are capable of bearing 

 very low degrees of temperature, for some only of its cells, according to Schumacher 1 , 

 were killed by a temperature of — 113.75 C, while others lived and retained their 

 powers of growth. 



On the other hand, many spores, especially those that are long-lived, can endure 

 extremely high temperatures without losing their vitality. Some observations show 

 that the length of the time to which they are exposed to the heat is an important 

 element in the case. The dry spores of a certain number of Fungi are not killed by 

 a heat which considerably exceeds ioo° C. According to Nageli it maybe said that 

 a temperature of i30°C. is necessary to secure their destruction. But the death-point 

 of the spores of Fungi is often much lower than this in water or watery vapour, and 

 it has not been shown that any can under these circumstances survive a temperature 

 of ioo° C. 



According to H. Hoffmann the dry spores of Ustilago Carbo and U. destruens 

 support unharmed a temperature of from 104 to 128 C. ; the spores of U. Carbo are 

 killed in a chamber filled with vapour at a temperature between 58°.5° and 62 ° C, 

 those of U. destruens by a temperature of from 74 to 78 ° C. in the space of an hour, 

 and by one of from 70 ° to 73 ° C. in 2 hours. Tilletia Caries, on the other hand, will 

 bear according to Schindler a temperature of 95 C. if dry, but not more than that. 

 According to Payen 2 the spores of a mould found in bread, Oidium aurantiacum, can 

 endure a temperature of 120 C. ; at 140 ° C. they were discoloured and killed. 



Pasteur's researches showed that the spores of Penicillium glaucum remain 

 unaltered in dry air at a temperature of 108 ° C. Many, but not all, lose their power of 

 germination at 1 19 to 120 C. ; all lose it very quickly if the temperature is raised to 

 between 127 and 132 ° C. The limit is similar in ' Ascophora elegans ' (a species of 

 Mucor). Similar results were obtained from experiments on some spores of uncertain 

 origin mixed with dust, among which Botrytis cinerea, P. (gonidia of Peziza Fuckeliana) 

 or a closely allied form may be certainly distinguished; these bore a temperature 

 of 120 C. Spores suspended in a fluid which was heated up to ioo° C. were always 

 killed in Pasteur's experiments. 



Against these statements must be placed the results of Tarnowsky's researches 

 communicated by Sachs 3 , according to which spores of Penicillium glaucum and 

 Mucor stolonifer when heated in air to a temperature of from 70 to 8o° C. during 

 1-2 hours very seldom germinated, and were killed by a temperature of from 82 C. to 

 84 C. ; they lost all vitality when warmed in a fluid up to from 5 1° to 55 ° C. We may 

 just mention some older statements of J. Schmitz 4 on this subject, which certainly 

 stand much in need of investigation. 



The foregoing statements show that the spores of the Fungi are similar in 

 character to the organs with analogous functions in other plants. They afford 



1 Sitzgsber. d. Wiener Acad. 70, 1 Abth. Juni, 1874, where other literature is cited. See also 

 Pfeffer, Physiol. II, 438. 



2 Compt. rend. XXVII, p. 4. 



3 Lehrb. Auflage 4, p. 699. 



4 Verhandl. d. naturh. Ver. d. Rheinlande, II (1845). 



