488 Influence of Temperature of Liquid Hydrogen on Bacteria. 



to strengthen my position with regard to the truly palseolithic 

 character of the implements found in other parts of that vast con- 

 tinent, and I am tempted to bring for comparison some few specimens 

 from South Africa. One of these, found by Mr. J. C. Eickard at the 

 junction of the Riet and Modder twenty years ago, is almost indis- 

 tinguishable from those of the Lac Karar, as is also one from the 

 valley of the Embabaan in Swaziland. But the most remarkable is an 

 implement of typically palaeolithic character found in 1873 under 

 9 feet of stratified beds at Process-fontein, Victoria West, by Mr. E. J. 

 Dunn.* May the day be not long distant when researches for the 

 implements of palaeolithic man may again be carried on, and trenches 

 be dug in South Africa for peaceful instead of warlike purposes. 



"Influence of the Temperature of Liquid Hydrogen on Bacteria." 

 By Allan Macfadyen, M.D., and Sydney Rowland, M.A. 

 Communicated by .Lord Lister, P.R.S. Received and read 

 May 31, 1900. 



In a previous communication we have shown that the temperature 

 of liquid air has no appreciable effect upon the vitality of micro- 

 organisms, even when they were exposed to this temperature for one 

 week (about - 190° C.).t 



We have now been able to execute preliminary experiments pro- 

 jected in our last paper as to the effect of a temperature as low as that 

 of liquid hydrogen on bacterial life. As the approximate temperature 

 of the air may be taken as 300° absolute, and liquid air as 80° absolute, 

 hydrogen as 21° absolute, the ratio of these temperatures roughly 

 is respectively as 15 : 4 : 1. In other words, then, the temperature of 

 liquid hydrogen is about one-quarter that of liquid air, just as that of 

 liquid air is about one-quarter of that of the average mean tempera- 

 ture. In subjecting bacteria, therefore, to the temperature of liquid 

 hydrogen, we place them under conditions which, in severity of 

 temperature, are as far removed from those of liquid air as are those 

 of liquid air from that of the average summer temperature. By the 

 kindness of Professor Dewar, the specimens of bacteria were cooled in 

 liquid hydrogen at the Royal Institution. The following organisms 

 were employed : Bac. acidi lactici, B. typhosus^ B. diplitherice, Proteus vul- 

 garis, B. anthracis, B. coli communis, Staphylococcus pyogenes aureus, 

 Spirillum clwlerm, B. phosphor escens, B. pyocyaneus, a Sarcina, and a 

 yeast. 



The above organisms in broth culture were sealed in thin glass tubes 



* See also a paper by M. E. T. Hamy in tlie ' Bulletin du Museum d'Histoire- 

 Natiirelle,' 1899, No. 6, p. 270. 



t ' Eoy. Soc. Proc.,' February 1, 1900 ; ibid., April 5, 1900. 



