ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 359 



lesions of the mesenteric glands, but no tubercle elsewhere. Inoculations 

 from these infected glands into a rabbit were without effect, the infer- 

 ence being that the lesion was innocuous, and that the animal had 

 recovered from the infection. 



Purification of Water by Ozone.* — D. Rivas finds that, under 

 favourable conditions, ozone reduces the number of bacteria in water, 

 and eliminates the Bacillus coli coniinunis. It oxidises ammonia-forming 

 nitrates. When the water was rich in organic matter the germicidal and 

 chemical actions of ozone were only partial. The author considers that 

 ozonisation is a favourable method for the purification of water such as 

 is usually obtainable for a town supply. He gives detailed descriptions 

 of his methods for obtaining and applying the ozone. 



* Centralbl. Bakt., 2te Abt., xvii. (1906) p. 506. 



•4* ^ I » 



