844 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
With regard to specific forms of pathogenic bacteria: — 
(i.) Spirillum cholerse asiaticse. Very conflicting statements are given 
as to the length of time in which it lives in water, but all agree that it 
can be conveyed by water, and is not, as a rule, very resistant towards 
competing forms. 
(ii.) Bacillus typhosus seems, in most cases, to be much more resistant 
than the cholera-spirillum. 
(iii.) Bacillus anthracis forms spores which may live in sterilized water 
for months without injury, if the temperature be not too high. 
(iv.) Streptococcus erysipelatis is very susceptible to immersion in 
water. 
(v.) Bacillus tuberculosis has been found to live for more than 115 
days in distilled water, and 95 in river water. 
Bacteriological Examination of Air in Freiburg.*— Herr Welz has 
made a systematic examination of the air in and about Freiburg for the 
purpose of ascertaining the number and variety of the Schizomycetes 
which might occur under different conditions. The researches were 
prolonged over a whole year, and carried out under various weather con- 
ditions. The air was taken from four different situations : — (1) the 
garden of the Botanic Institute ; (2) a room in a dwelling-house in the 
middle of the town ; (3) a ward of a hospital ; (4) a mountain 738 m. 
high, about two leagues distant from the town. 
The method adopted simply consisted in sucking the air into flasks 
filled with sterile fluid. After the aspiration was finished, 1 ccm. of the 
fluid was mixed with 10 ccm. of nutrient gelatin. Observations were 
made on the plates for 14 days to 3 weeks, and it was found that aerial 
Schizomycetes grew far more slowly even under favourable conditions 
than those taken from water or the soil. In each experiment 10 litres 
of air were used. On the whole it was found that in warm weather the 
Schizomycetes were more numerous than in cold or rainy weather. Fogs 
appeared to exert a notable influence on the multiplication of bacteria, 
for except in cold November fogs they were much increased. 
In the middle of August yeast fungi began to appear, attaining their 
maximum in October. Later on, and in rainy times, mould fungi were 
predominant. 
The air taken from the mountain showed no quantitative or qualitative 
differences as to Schizomycetes, although it had considerably less mould 
fungi than the town air. 
No important difference could be detected between the air taken from 
open places and that from close’ human dwellings, provided the latter 
were in good sanitary condition. On the other hand, when the latter 
places were in unhygienic conditions, the Schizomycetes increased, and 
the appearance of pathogenic fungi (St. pyogenes aureus ) was observed. 
In open places near a large town these conditions seemed to have 
some influence on the air, while in that taken from the mountain the 
quantity of Schizomycetes was less, and their distribution more equal. 
The author ends by giving a list of bacteria found, but it is too 
long to quote in extenso. 
* Zeitschr. f. Hygiene, xi. p. 121. See Centralbl. f. Bakteriol. u. Parasitenk., xi. 
(1892) pp. 630-2. 
