1912.] Certain Results of Drying Non-sporing Bacteria. 129 



afterwards inoculated. The immediate drying of the slips after the inoculation 

 was carried out in the incubator at 37° O, in which they were kept for 

 about 15 minutes. 



Some of the slips were, within the course of an hour or so, transferred to 

 the tubes, from which the air was thereupon exhausted ; the rest were stored 

 in the Petri dish in the dark. The bacterial suspensions first used were made 

 by adding boiled water to a recent agar or jelly slope culture ; all the later 

 suspensions were cultures in peptone water (with 1-per-cent. sodium 

 chloride). 



In order to test the vitality of the bacilli after drying, whether in vacuo or 

 in the air in the Petri dish, the slips were transferred to test-tubes of litmus 

 glucose broth, and incubated for many days at 37° C. The broth tubes were 

 proved to be sterile before use, by a preliminary incubation. 



We may now proceed to detail the observations, and afterwards to 

 comment on the results. 



Bacillus coli. 



The first experiments were made upon this bacillus, on October 14, 1910. 



One vacuum tube was sealed off after three full days' connection with 

 the charcoal tube, i.e. on the fourth day ; and a second on the 6th day, the 

 vitality of the micro-organism being tested as above described. In both cases 

 it was dead. The control air-dried film was also found to be dead on the 

 4th day. 



Bacillus typhosus. 



Vacuum tubes were sealed off on the 4th day and on the 6th. 



The bacillus in both proved to be dead. The control air-dried films were 

 likewise dead on the 4th day. The exact day on which the air-dried micro- 

 organism dies can be, of course, readily determined by transferring an 

 inoculated slip daily to the broth medium. 



Different strains or samples of the same bacillus vary within certain 

 limits. In an observation so made, using for the inoculation a suspension 

 of B. typhosus in water from an agar slant of 24 hours' growth, the bacillus 

 died on the 4th day. In four experiments made with a 24 hours' growth 

 in peptone water of B. typhosus, the micro-organism died, in one case, 

 on the first day (i.e. within 24 hours); in two cases, on the 4th day; and in 

 the fourth case on the 5 th day. 



Staphylococcus pyogenes aureus. 

 This is more resistent to desiccation, both ia vacuo and in the air, than 

 either of the preceding. In one experiment vacuum tubes were sealed off on 



VOL. LXXXV. — B. K 



