270 FRAGMENTS OF SCIENCE. 



the common practices of life. Heat kills the bacteria, 

 colds numbs them. When my housekeeper has pheasants 

 in charge which she wishes to keep sweet, but which 

 threaten to give way, she partially cooks the birds, 

 kills the infant bacteria, and thus postpones the evil day. 

 By boiling her milk she also extends its period of 

 sweetness. Some weeks ago in the Alps I made a few 

 experiments on the influence of cold upon ants. Though 

 the sun was strong, patches of snow still maintained 

 themselves on the mountain slopes. The ants were 

 found in the warm grass and on the warm rocks adja- 

 cent. Transferred to the snow the rapidity of their 

 paralysis was surprising. In a few seconds a vigorous 

 ant, after a few languid struggles, would wholly lose 

 its power of locomotion and lie practically dead upon 

 the snow. Transferred to the warm rock, it would 

 revive, to be again smitten with death-like numbness 

 when retransferred to the snow. What is true of the 

 ant is specially true of our bacteria. Their active 

 life is suspended by cold, and with it their power of 

 producing or continuing putrefaction. This is the 

 whole philosophy of the preservation of meat by cold. 

 The fishmonger, for example, when he surrounds his 

 very assailable wares by lumps of ice, stays the 

 process of putrefaction by reducing to numbness and 

 inaction the organisms which produce it, and in the 

 absence of which his h'sh would remain sweet and sound. 

 It is the astonishing activity into which these bacteria 

 are pushed by warmth that renders a single summer's 

 day sometimes so disastrous to the great butchers of 

 London and Glasgow. The bodies of guides lost in 

 the crevasses of Alpine glaciers have come to the 

 surface forty years after their interment, without the 

 flesh showing any sign of putrefaction. But the most 

 astonishing case of this kind is that of the hairy 



