65 



slants in test tubes, to - 5° to - 1° for 6 weeks, or to - 78° 

 for 7 lionrs, or to - 185° for ^ hour. The plants were not 

 killed. 



Karcher (1931) cultured several genera of fungi on 

 agar slants in narrow test tubes, and, when the colonies 

 had spread over about j of the surface of the agar, she 

 exposed them to varying degrees of cold. Coprinus was 

 killed when the temperature of the agar was lowered to 

 -40°, even when it was thereupon immediately thawed. 

 Lepiota, Boletus, and the submerged mycelia of Phy- 

 comyces were similarly killed by a momentary exposure 

 to -60°. The mycelia of the following survived a 1- to 

 8-day action of -70° as well as a 13-hour exposure to 

 liquid air: Collyhia, Schizophyllum, Hypholoma, Clito- 

 cyhe, Placodes, Armillaria, Xylaria, Aspergillus (spore- 

 bearing, and young spore-free mycelia) and Phyconiyces 

 (mycelia with sporangia). 



Lipman (1937), considering that the fungi used by 

 Karcher might have formed spores (the same objection 

 could be raised against most of the above described in- 

 vestigations), undertook a series of experiments in which 

 he made sure by direct observation that the fungi experi- 

 mented upon were in the actively growing state, that no 

 spores were present at the moment of the treatment. 

 Twelve species of fungi belonging to the genera, Asper- 

 gillus, Penicillium, Rhizopus, Mucor, Ahsidia, Mortier- 

 ella, Rhizoctonia, Armillaria, Trichoderma, Pythium and 

 Fusarium, were cultivated for 24 or 48 hours on synthetic 

 agar-media or on potato-agar. The cultures, on slants in 

 sealed test tubes, were immersed in liquid air for 48 hours. 

 The previous cooling and the subsequent warming were 

 gradual. In 14 cultures out of 26, and in 8 species out of 

 12, Lipman observed some grow^th, either in the tubes in 

 which the fungi were treated or after a transfer to fresh 

 media. A Rhizopus, a Rliizocionia, an Aspergillus and 

 an Armillaria were killed. A higher percentage survived 

 when exposed to low temperatures at the age of 48 hours 

 than when exposed at the age of 24 hours and the author 



