at tlie Royal lastitation, 1 900-1 907. 39i> 



material purified under the direction of Dr. Thorpe, which he has- 

 shown to have an "atomic weight" practically the same as that origi- 

 nally deduced for radium by Madame Curie. This material was pre- 

 pared at the expense of a grant of 1000/. made to the Royal Society 

 by the Goldsmiths' Company specially for the purpose of promoting 

 the study of the properties of radium — of all substances known to us 

 the most mysterious and exceptional in its behaviour. 



Maintenance of Vitality at Low Tempekatures. 



Dr. Macfadyen's earlier experiments on this subject were re- 

 ferred to by Miss Clerke. He has stated in a later communication 

 that no impairment of the vitality of bacteria is conditioned by their 

 continued exposure to the intense cold of liquid air even for a period 

 of six months. That all chemical action should come to an end at 

 such temperatures was to be expected ; Dr. Macfadyen's remarkable 

 observations, however, establish the important fact that bacteria may 

 be frozen without being ruptured or their minute mechanism dis- 

 located — that, in fact, they resemble in behaviour a watch, which 

 stops when frozen, because the oil used as a lubricant is congealed, 

 although when the temperature is raised and the oil melts it is easily 

 started into activity from its state of suspended animation. In the 

 organism, water is the lubricant, as it were ; the once congealed 

 organism starts into life again so soon as the water is liquid and food 

 materials can circulate in it and g{iin access to the enzymic centres 

 at which they undergo constructive and oxidative changes. 



A further use has been made of liquid air h\ Dr. Macfadyen which 

 may well prove to be of great importance. He has shown that by 

 triturating micro-organisms in the hardened condition to which they 

 are reduced l)y cooling in liquid air, it is possible to lilierate the cell 

 contents by purely mechanical means. 



The fluid thus obtained from typhoid organisms is found to be- 

 effective as an immunising and curative agent against typhoid fever 

 when injected into the monkey. 



Moreover, it is clear that the luminosity of phosphorescent 

 organisms referred to above is due to a vital process, as the effect is no 

 longer noticeable after disintegrating the organisms at the temperature- 

 of liquid air. 



The Liquefaction of Helium. 



The liquefaction of helium was effected on July Dth 1908, in the 

 Physical Laboratory of the University of Leiden, by Professor 

 Kammerlingh Onnes, who thereby achieved the conspicuous success 

 his systematic studies of the properties of gases, carried on with 

 great skill and unremitting perseverance during several years past, so 

 richly deserved. In describing his results. Professor Onnes has most 

 generously recognised the debt he is under to the Royal Institution : — 



