On Micro-organisms from Ice, &c. By Dr. Maddox. 455 



The difficulty is to find a suitable medium for nourishing or 

 rejuvenating all the aerial germs that have been gathered by the 

 aspirator. 



The great extremes of heat and cold to which the spores of 

 many of the Schizophytes have been exposed without loss of vitality 

 is a point of much interest. The Rev. Mr. Dallinger, in his 

 careful experiments, found the death-points in dry heat, for the 

 mature monads that he had studied, to range from 138° F. to 

 142° F., but their spores supported for five to ten minutes 250° to 

 300° F. ; whilst the same heated in fluid were destroyed at 212° 

 to 268° F. M. Van Tieghem found some micrococci and bacilli to 

 flourish at 74° C. M. Miquel cultivated one form from the Seine 

 at 70° C, which died when the temperature was raised to 72° C. 

 Professor Frisch finds that the bacteria seen in diphtheritic 

 exudation and in puerperal fever resist a minus temperature of 

 87 "5° C. without destruction, and the bacilli spores to resist 

 extremes of cold better than the rods. M. Miquel states that a 

 particular Bacterium found in snow resisted a temperature of 26° 

 to 30° C. below freezing for three hours, and for more than twenty 

 days a mean temperature below zero of 2 ' 5° C. The enumera- 

 tion of such experiments might be greatly multiplied. 



Drs. Cohn and Mendelsohn state that it required a powerful 

 galvanic battery current of five elements to destroy the vitality of 

 the bacteria they experimented upon. 



Not to quote more largely, it seems quite incomprehensible 

 that such minute organisms should be able to resist such extremes 

 of temperature, and that the so-called mucous, gelatinous, albu- 

 minoid, cellulose, or by whatever name it may pass, covering, 

 which is permeable to fluids, should be able to defend the living 

 contents against such extraordinary variations of heat and cold. 

 Here, under the hand of most careful experimenters, the reasonable- 

 ness of previous doubt must give place and credence to the senses. 

 Can it be that the envelope that surrounds the organism normally, 

 when subjected to dry heat, dries so entirely and rapidly as to 

 prevent the entire loss of moisture from within, or that the encap- 

 sulation, so to speak, is so perfect, that there is no room for the 

 generation of high-pressure steam, and that under moist heat 

 the coagulation is so effective that it shrinks the outer material so 

 closely upon the contents, that steam cannot be generated except 

 under rupture? Or can the rapid chemical changes they can 

 effect, suffice to continue their vitality under such abnormal 

 conditions ? 



"We may largely theorize, though I fear only to record our 

 ignorance, when we attempt to limit the manifestations of life by 

 predeterminate lines, derived from the study of higher organisms, 

 though amongst these there are some, as the Aphides, stated to 



