METHOD OF DESCRIBING CULTURES 61 



Color of cream-ring. 

 Odor. 



In milk the presence or absence of coagulation and 

 proteolysis should always be noted. Com- 

 pare your culture always with a sterile con- 

 trol milk-tube. 

 IX. Broth-culture. 



Cloudiness: degree and uniformity, scum: ring- 



or island-shaped. 



Precipitate, observed by shaking. Color, forma- 

 tion, diffusibility, viscidity, amount. 

 X. Solidified blood-serum. 



Describe like agar-slant, and note presence or 



absence of liquefaction. 

 XI. Fermentation-tubes. 



Gas-formation in closed arm, percentage and 

 relation of carbon dioxid to hydrogen expressed 



TT 



by the formula . 



LUp 



Growth in both arms or in one arm only, observed 



by cloudiness. 

 Reaction: acid or alkaline. 



Directions jor filling out the first page of culture- 

 charts (see Appendix III.) 

 I. Name the group and organism. 

 II. Read in the textbook or references given so as to 

 indicate the source and habitat. 



III. Name the most important references, and read 

 them. 



IV. Morphological characters. 



i. Describe the morphology as observed from 

 the stained preparation opposite the medium 

 from which obtained. 



