468 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Isolating Bacillus typhosus from Soil.* — Dr. S. Martin now uses 

 ordinary peptone broth in test-tubes, acids a small portion of the soil, 

 and then incubates for 4-6 hours at 37°. At the end of this time the 

 medium is usually slightly turbid. It is then brushed, without 

 recharging the brush, over the surface of six agar plates. Each plate 

 is examined under a low power after 24 hours incubation, and those 

 colonies which have any resemblance to typhoid are studied further. 

 The examinations of one testing extend over a period of three weeks. 

 Each colony is examined microscopically, and a broth culture made. 

 This culture is tested for indol after a lapse of 3 or 4 days, and from 

 it are also made sub-cultures on agar slopes, shake-glucose-gelatin, 

 milk, and potato. If the sub-cultures show typical typhoid bacilli, the 

 micro-organisms are further tested by determining the number of flagelia, 

 and by the serum reaction. 



Value of Plating as a means of Determining the Number of 

 Bacteria in Drinking Water.f — W. C. C. Pakes finds that plating upon 

 ordinary gelatin, whether made with distilled or ordinary tap-water, 

 gives no necessary criterion of the number of bacteria present. As far 

 as possible the gelatin should be made without meat extractives, with 

 the water to be examined, or with a sample of water similar in mineral 

 constitution. As a corollary to the foregoing, the only satisfactory 

 method of determining the contamination of water by sewage is to 

 ascertain the number of sewage organisms present in the water. 



New Hsemoglobinometer.J— -Dr. A. Dare describes a new instru- 

 ment for estimating the quantity of haemoglobin. Unmixed blood is 

 used, and the stratum is of constant thickness. The essential parts of 

 the instrument are an automatic pipette and a graduated colour-screen to 

 calculate directly the percentage of haemoglobin. The blood and the 

 comparison screen are placed side by side and inspected through a lens 

 fitted into a telescoping camera-tube. By means of a screw the colour 

 scale is rotated until the two tints correspond. 



Method for Increasing the Number of Tubercle Bacilli in Sputum 

 and Urine. § — Jochneann, after mentioning some artificial media in- 

 tended for the cultivation of the tubercle bacillus, points out that 

 Heyden-agar, by preventing the growth of other microbes, acts electively 

 towards tubercle. It seems to act best when slightly acidulated with 

 lactic acid, an orange-red pigment being formed. So, too, with acid 

 Heyden-broth, the growth was more copious than when the reaction was 

 alkaline. For increasing the number of bacilli in a sample of sputum 

 he used the following medium : — Heyden nutrient 5 grin., salt 5 grm., 

 glycerin 30 grin., normal soda solution 5 com., distilled water 1000 ccm. ; 

 20 ccm. of this bouillon were mixed with 10 ccm. of sputum, and incu- 

 bated for 24 hours at 37°. Then 3 ccm. of carbolic acid were added and 

 the sediment examined in the usual way. In the case of urine the 

 sediment obtained by centrifuging is treated in a similar manner. 



* Local Gov. Board Rep. 1899-1900 (1901) pp. 531-4. 

 t Centralbl. Bakt., 2" Abt., vii. (19(H) pp. 386-91. 

 t Bull. Johns Hopkins Hosp , xii. (1901) pp. 24-5. 



< Hygienische Rundschau, x. (1900) pp. 969-81. See Bot. Centralbl., lxxxv. 

 (1901) pp. 343-4. 



