THE STUD.Y OF MOLDS 109 



State the age of the culture. These cider tubes are then of 

 the proper age from which to make inoculations. 



5. Pure cultures of the two remaining molds will be 

 found in tumblers marked " Laboratory Cultures." 



Always leave such cultures in the place assigned, after 

 using. 



Make cultures of each of the four molds as follows: 



(a) Agar slant (for method see Exercise 15). 



(b) Agar plate (giant colony) . Use Roux culture flask for 

 Rhizopus nigricans (see pp. 2, 62). 



(c) Cider or wort (test-tube culture).* For method of 

 inoculation of c and d see pp. 60, 61. 



(d) Gelatin stab (test-tube culture). Keep all gelatin test- 

 tube cultures in cold-water bath or in a cool place (15 to 20 C). 



(e) Adhesion or moist-chamber culture. (See pp. 78-81). 

 Prepare these cultures from the freshly inoculated cider tubes. 



6. Make drawing of spores of each mold from adhesion 

 or moist-chamber culture as soon as preparation is made. 

 Measure the spores and record the limits of size. 



7. Draw the twenty-four hour cultures each of a, b, c, d, 

 and e and label in detail. Measure the spores which have 

 germinated in e, and record the diameter and length of the 

 mycelium. 



8. Make drawings of branched mycelium and several 

 stages of development of fruiting bodies from a glycerin 

 mount. This mount is most easily prepared from an agar 

 plate colony. 



9. Make drawings of all cultures as soon as a marked 

 development is seen over that of the preceding drawing. 

 Three drawings of each culture should be sufficient. 



10. Measure giant colony of each mold every day 

 and record the measurements. What is noted of the com- 

 parative rate of growth? 



All drawings must be made directly on charts or in note- 



* Cider cultures have already been made of the two molds isolated 

 from mixed culture. 



