BIOLOGIC CHARACTERS. 195 



are several days old, and note whether spores are being 

 formed. Note particularly the position of the spore 

 within the cell. Is the spore of smaller or greater 

 diameter than the cell in which it is forming ? Exam- 

 ine cultures that are a week or more old, and note 

 whether the organisms have undergone any definite 

 alterations in form (involution forms), or whether they 

 present evidences of fragmentation or granulation of 

 their protoplasm (degeneration forms). 



BIOLOGIC CHARACTERS. Colony-formation. Ob- 

 serve the character of the colonies formed in gelatin 

 and agar-agar plates. Describe a typical surface colony 

 and a typical deep colony, both as to their macroscopic 

 and microscopic appearance. What is the relative size 

 of the colonies formed on each of these media when 

 they are sufficiently separated from one another to permit 

 unhindered development ? Note the color and internal 

 structure of the colonies as well as their relative density. 

 What is the nature of the surface contour and arrange- 

 ment of the colonies ? Note their general character, as 

 to whether they are moist or dry, compact or loosely 

 constructed, sharply circumscribed or spreading over the 

 surface of the medium. Do the gelatin colonies show 

 evidences of liquefaction ? 



Agar-slant Inoculations. Observe the nature of the 

 growth on the surface of an agar-agar slant inoculation. 

 Describe the color, texture, and optical characters of the 

 growth. Is the growth confined to the line of inocula- 

 tion, or has it a tendency to spread over the surface of 

 the medium ? Is it smooth or rough, moist or dry, 

 glistening or dull in character ? If the organism forms 

 pigment, note whether the pigment is confined to the 

 area of growth or whether it extends into the medium 



