556 



SCIENCE 



[N. S. Vol. XXXI. No. 797 



ABSOLUTE GAS PBODUCTION 



Total gas per 100 c.cm. medium 1.4 c.cm. 



OO, 92% 



Hs 3% 



Nj (by difference) 5% 



By means, however, of an improved gas analysis 

 apparatus devised by Dr. Keyes it was found 

 possible to analyze accurately such small amounts. 

 The results for 15 days' growth were as follows: 



Exper. I. 

 Total gas obtained . . . 3.49 c.cm. 

 Total gas per 100 c.cm. 



medium 2.55 c.cm. 



CO, 93.25% 



H, 2.03% 



Nj (by measurement) 4.44% 

 99.72% 



Exper. II. 

 5.89 c.cm. 



2.32 com. 

 97.10% 



2.12% 



■77% 



99.99% 



Experiment II. probably approaches nearest the 

 truth, as the leakage of only a trace of air into 

 the bulb during incubation would easily suffice to 

 falsify the figure for nitrogen. 



Substitutes for Loffier's Bloodserum for the Diag- 

 nosis of Diphtheria: W. W. Bbowne, Brown 

 University. 



Attempts were made to grow the diphtheria 

 bacillus on Hadley's medium,'' solidified with 5 

 per cent. agar. Growth on this medium was 

 atypical. Albumen was then substituted for the 

 glycocoU of Hadley's medium, but on sterilization 

 the albumen was coagulated as a flocculent precipi- 

 tate through the medium. The grovi^th was scanty. 

 Attention was now turned to egg as a source of 

 albumen. Egg was mixed with dextrose broth in 

 the ratio of 1 part of broth to 3 of egg and coag- 

 ulated. The medium was hard and firm. The 



"Journal of Infectious Diseases, Supp. 3, May, 

 1907, p. 95. 



slow growth of the bacillus on this medium would 

 prevent its use in the diagnosis of diphtheria. 



Alkaline albuminate was then substituted for 

 the albumen. Although the albumen was not 

 coagulated by heat, nevertheless, it was precipi- 

 tated by the acid produced by the bacillus. The 

 growth on this medium was satisfactory, but the 

 precipitation of the albumen prevented ready diag- 

 nosis. Acid albumen, on the other hand, showed 

 scanty grovrth. 



Next, a 6 per cent, solution of commercial 

 albumen was mixed with dextrose broth in the 

 ratio of 1 part of broth to 3 of albumen. This 

 medium when coagulated presented a hard firm 

 surface. The bacillus seemed to grow well upon 

 it and diagnosis from throat cultures was fairly 

 easy. While this medium does not seem to be a 

 perfect substitute for the Loffier's serum, yet, in 

 times of scarcity, it might be used to good ad- 

 vantage. 

 The Hygiene of the Smmming Pool: John W. M. 



BuNKEE, Brown University. 



The swimming pool is liable to be a source of 

 contagion if the water is used for any length of 

 time. Cases of ear and nose affections have been 

 traced to this source. Typhoid is apt to enter the 

 pool and spread therefrom, and unless an abun- 

 dant supply of water is available, the expense of 

 frequent renewal is prohibitive. 



Filtration is the method of purification ordi- 

 narily employed, but usually yields only partial 

 purification, inasmuch as only a small part of the 

 water of the pool is removed, filtered and returned 

 to the pool. The filter at Brown University has a 

 high efficiency and keeps the water of the pool a 

 good color, but the bacterial content of the pool 



Sterilization by heat is out of the question 

 because of expense. Sterilization by the addition 

 of chemicals has proved effective in the case of 



