242 



Cincinnati Society of Natural History. 



Ai . 



Morphology. — Medium sized micrococcus. Single, twos, 

 and fours. Stains readily. Size about i !>■. 



Gelatin Stab. — Abundant growth, decreasing downward. 

 Abundant yellowish surface growth. No liquefaction. 



Glucose Gelatin. — Slight growth. No gas. 



Gelatin Slant. — Growth finally becomes quite abundant. 

 White, with yellowish tinge. Shiny and slightly irregular. 

 No liquefaction. 



Agar Slant. — Abundant growth, cream-colored, but turns 

 yellow in time. Moist, spreading, shiny. 



Bouillon. — Slight cloudiness with considerable precipitate. 



Milk. — Casein is digested without previous precipitation, 

 after two weeks. 



Potato. — At first slight growth, but this increases slowly. 

 Dry and wrinkled. Color changes from pale yellow to a 

 decided yellow. 



Conclusions. 



1. The air bacteria of our semi-desert region presents a 

 somewhat limited flora ; but this is found to be widely dis- 

 tributed, due undoubtedly to the high winds which sweep 

 uninterruptedly over our wide stretches of nearly barren 

 mesas. 



2. The actual number of bacteria contained in the air is 

 not as large as in fertile and cultivated regions, but the num- 

 ber is not as small as is popularly supposed. 



3. It would seem to follow from the above that sanitary 

 measures and precautions should receive practically the same 

 attention here as elsewhere. Disease-bearing materials, such 

 as infected clothes, sputum, etc., should be carefully disin- 

 fected or burned. 



4. Many of the species show highly - colored colonies; 

 these belong mostly to the group of micrococci. The flora 

 is characterized by its inertness toward sugar media, and its 

 failing to peptonize gelatin. 



5. Apparently none of the species have been previously 

 described. 



32 



