228 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Rate of Multiplication of Micro-organisms.* — A. G. M'Keudrick 

 and M. Kesava from a mathematical study draw the following conclu- 

 sions: — 1. The rate of multiplication of fast-growing micro-organisms 

 is proportional to the number of organisms and to the concentration 

 of foodstuff. 2. The initial rate of multiplication affords a factor of 

 comparison both of efficiency for media and of reproductive properties 

 of organisms. 3. Vaccines may be prepared in large quantities on the 

 basis that a maximum number of organisms is attained to, this maximum 

 being dependent on the concentration of nutriment, and independent of 

 the amount of culture inoculated. 



New Specific Character of the Human and Bovine Bacilli of 

 Tuber culoBis.f — P. Chausse made inhalation experiments on the cat and 

 dog with the natural products of human and bovine tuberculosis, the 

 material used being sputum and caseous matter. It was found that these 

 domestic carnivora were more sensitive to the bovine than to the human 

 tubercle ; this result affords a strong presumption in favour of the re- 

 ceptivity of human beings for bovine tuberculosis. 



Bacteria of Frozen Soil.$ — H. J. Conn records the results of a series 

 of experiments on frozen soil in reference to the number of bacteria 

 present. The winter flora were found to differ materially from those 

 cultivated in the summer. In most instances a temperature approach- 

 ing freezing-point inhibits growth, but certain bacteria flourish when 

 cultivated at low temperature, and even in ice It would appear, there- 

 fore, that the red notion of temperature inhibits the growth of the summer 

 bacteria, and indirectly permits the winter forms to flourish. 



ZiPFBL, H. — Beitrage zur Morphologie und Biologie der KnoUchenbakterien der 

 Leguminosen. Centralbl. Bakt., 2ie Abt., xxiii. (1911) pp. 97-137. 



* Proc. Roy. Soc. Edinburgh, mi. (1912) pp. 649-55. 



t Comptes Rendus, cliv. (1912) pp. 143-4. 



X Centralbl. Bakt., 2te Abt. xixii. (1911) pp. 97-137. 



-*-^^ I •• 



