232 



SUMMARY OF CURRENT RESEARCHES RELATING TO 





• 1 p.c. urotropin agar, a very slight and delayed growth occurred in 

 - 5 p.c, while only one colony was obtained on 1 p.c. at the end of 11 

 days' incubation at 37° C. A paratyphoid bacillus (L.) gave a good 

 growth in ' 1 p.c. urotropin broth, a fair growth in • 5 p.c, and a faint 

 growth in 1 p.c, which was considerably delayed. 

 A paratyphoid bacillus (S.) gave a similar result 

 in 0*1 p.c and • 5 p.c, but failed to grow in 

 1 p.c urotropin broth. B. pyocyaneus gave an 

 abundant growth in all three strengths of the 

 urotropin medium. The author stated that these 

 experiments were being continued and various 

 modifications were being tried. 



New Method of Isolating Bacillus typhosus 

 from Infected Water.* — H. S. Willson's method is 

 as follows. A stock solution of alum in distilled 

 water, 10 grm. to 100 ccm., is used; 0*5 grm. 

 alum is added to each litre of infected water. The 

 whole is well stirred, and a known quantity with- 

 drawn and centrifuged for 15 minutes at 2000 re- 

 volutions, the supernatant fluid save 1 ccm. poured 

 off, the residue stirred and plated on the Drigalski- 

 Conradi medium and incubated at 42° C. for 24 

 hours, the resulting colonies being tested by the 

 agglutination method and subcultures. Numerous 

 experiments were performed with water infected to 

 a known amount, and some on a large scale in gal- 

 vanized iron tanks. In these tanks the bacilli died 

 out in 6 days, owing to the action of the zinc-iron 

 coating. 



In conclusion, the author advocates the con- 

 version of the suspected water into a nutrient 

 medium (water -f- 1 p.c. nutrose 4- " 5 p.c. caffeine 

 4- 0*001 p.c. crystal violet) by the caffeine method, 

 which enriches the B. typhosus at the expense of 

 the other organisms ; but on account of the vari- 

 ability in action it should be supplemented by the 

 precipitation process. 



Method for keeping Cultures Alive indefi- 

 nitely, f — P. Murillo records the following method 

 for keeping cultivations of bacteria alive for protracted periods. A 

 collodion sac made in the usual way is fitted over the lower end of a 

 piece of glass tubing. The tube is adjusted in the neck of an Erlen- 

 meyer's flask by means of a perforated rubber stopper. The tube and 

 the flask are then filled with a suitable quantity of broth, and after the 

 tube has been plugged with cotton wool the whole apparatus (fig. 33) 

 is sterilised. Inoculations are then made in the usual way. The appu- 



Fig.133. 



* Journ. Hygiene, v. (1905) No. 4. 



t Bol. Inst. Alfonso XIII. , i. (1905) pp. 180-91 (5 figs.). 



