350 BULLETIN No. 161 [November, 



Scries 2. Pure Cultures 



Before the close of the first series it was recognized that these 

 experiments were of such importance that a repetition of the same 

 was advisable. 



PREPARATION ^ le cu ltures used and the preparation of the 

 OF EMULSIONS emulsions were similar to that in Series I. 



Emulsion of the Human type. The sample of 

 water used for the emulsion of the human type was obtained from 

 the pool June 15, 1911. With the sample was obtained also a 

 considerable amount of floating green and yellow sediment scraped 

 from the inside of the large tiling enclosing this pool of water. A 

 microscopic examination showed very abundant algae anabena, 

 diatoms, desmids, scenedesmus, and confervoideae ; also several 

 kinds of bacteria. Among the animalcule there were vorticellae, 

 amoeba, a few paramoecium, water-eels and rotifers. 



There were thoroly shaken 450 cc. of this algal water to which 

 was added an emulsion of approximately 5 mg. of human tubercle 

 bacilli. This sample was divided into two equal portions : one 

 portion was placed in an unglazed earthen, cylindrical jar eight 

 inches tall and three inches in diameter; the other portion was 

 placed in a small, unglazed vase which was stopped tightly with 

 a one-hole rubber stopper in which was inserted a small glass tube 

 that reached above the surface of the water and allowed the escape 

 of any gases that might accumulate in the vase. This vase was 

 placed on the bottom of the courtyard pool twenty inches below 

 the surface of the water. The other sample in the 8-inch jar was 

 placed on a slate shelf four inches below the surface of the water. 

 This jar was open to the sunlight but the direct sun could not 

 reach the surface of the emulsion inside. During the winter the 

 part of this jar projecting above the surface of the water! was 

 crumbled by freezing. (See Fig. i.) 



Emulsion of the Bovine type.' The emulsion of the bovine 

 type was made in a way similar to that of the human type. Five 

 milligrams of these organisms from a young culture on glycerine 

 egg were removed and rubbed up thoroly in a sample of 225 cc. 

 of water obtained from the drinking trough at the dairy cattle 

 barns, and thoroly mixed. A microscopical examination showed 

 the following: (a) vegetation spirogyra, . oscillaria (large and 

 small species, the small species being very abundant), a few dia- 

 toms, abundant protococcus, desmids, scenedesmus and anabena ; 

 (b) animalcule -amoeba, paramoecia, stylontia and vinegar eels. 



This sample was placed along with the emulsion of the human 

 type in a similar cylindrical jar on the slate shelf below the sur- 

 face of the water in the pool. 



