478 SUMMARY OF CURRENT EESEARCHES RELATING TO 



experiments milk inoculated with a coccus which possessed the unique- 

 property of retaining its vitality at temperatures considerably above 

 60° C, and concluded that the efficacy of the method depends upon the 

 conditions under which the exposure is made : if pasteurisation at 

 80° C. is carried on whilst the milk is exposed to the air, a " scalded 

 layer " pellicle formation occurs, and the organisms caught up in this 

 layer acquire greater powers of resistance than such organisms as re- 

 main suspended in the milk below, a result partly due to the lower 

 temperature existing at tho surface, but depending chiefly upon the 

 nature of the enclosing membrane. An interesting fact observed in 

 the course of these experiments was that if the membrane was removed 

 from the milk after an interval of about 10 minutes after formation,, 

 a second membrane then formed, which proved to be perfectly sterile,, 

 although the first membrane contained living organisms at the time of 

 removal. 



Decomposition of Lactose by Bacillus acidi lactici.* — P. Haacke 

 states that when milk-sugar is decomposed by the B. acidi lactici, the 

 resulting products consist of lactic acid, acetic acid, and alcohol, together 

 with a gas which was not analysed. The amount of sugar decomposed 

 by 1000 bacilli varies according to the conditions from 0*008 mg. to 

 0-00001 mg. The quantity of lactic acid obtained never exceeds one- 

 third of the sugar decomposed, whilst the amount present at any given 

 moment is not strictly proportional to the quantity of sugar decom- 

 posed, as a portion of the acid is probably acted upon still further. 



Bacillus tuberculosis in Cheese.f — Harrison carried out a careful 

 series of experiments to determine the length of time the B. tuberculosis 

 would remain alive and virulent in Cheddar cheese manufactured from 

 infected milk. In all twenty-seven guinea-pigs were inoculated with curd 

 or cheese at intervals of about one week: up to the 112th day after the 

 commencement of the experiment, with the result that the presence of 

 the B. tuberculosis could not be demonstrated after 62-70 days. As com- 

 pared with similar experiments carried out in 1900 at Berne with Swiss 

 Cheddar, this shows a difference of about 34 days in favour of Canadian 

 Cheddar ; and Harrison suggests that the difference may be due to the 

 higher acidity, the intimate admixture with salt, and the closer texture 

 of the Canadian cheese. 



Bacillus tuberculosis in Buda-Pesth Butter. $ — Anjeszky examined 

 twenty samples of butter obtained from different sources, in order to 

 determine the presence or absence of the tubercle bacillus. Three or 

 four healthy guinea-pigs of 850-450 grm. weight were injected intra- 

 peritoneally with 0*5 to 2 ccm. of the fat-free centrifugalised deposit 

 from each sample. The animals inoculated with three of the samples 

 died within a few days from infection by the Streptococcus pyogenes, 

 Staphylococcus aureus, and the B. coli communis respectively. Of tho 

 remainder, three only (17-6 p.c.) developed general tuberculosis, to 

 which they succumbed in from 35-80 days. Some of the animals 

 inoculated from each of the other fourteen samples of butter were killed 

 4 or (5 weeks after inoculation and carefully examined, but with negative 



* Arch. Hygiene, xlii. (1902) pp. 16-47. 

 t Centralbl. Bakt, l t0 Abt., xxxi. (1902) pp. 250-1. X Tom. cit., pp. 132-4. 



