274 METHODS OF IDENTIFICATION AND STUDY 



tive forms are present, and observe the process of 

 germination in. a similar manner. 



The comfort of the microscopist is largely enhanced 

 in those cases where the period of observation is at all 

 lengthy, by use of some form of eye screen before the 

 unemployed eye, such as is figured on page 58 (Fig. 49). 



If it is impossible to carry out the method suggested 

 above, proceed as follows : 



(a) Spore Formation. Plant the organism in broth 

 and incubate under optimum conditions. 



At regular intervals, say every thirty minutes, re- 

 move a loopful of the cultivation and prepare a cover- 

 slip film preparation. 



Fix, while still wet, in the corrosive sublimate fixing 

 solution. 



Stain with aniline gentian violet, and partially de- 

 colourise with 2 per cent, acetic acid. 



Mount and number consecutively ; then examine. 



(b) Spore Germination. Expose a thick emulsion of 

 the spores to a temperature of 80 C. for ten minutes 

 in the differential steriliser (vide page 257). 



Transfer the emulsion to a tube of sterile nutrient 

 broth and incubate. 



Remove specimens from the tube culture at intervals 

 of, say, five minutes. 



Fix, stain, etc., wet, as under (a), and examine. 



(B) Fixed. 2. In stained preparations. 



(a) To determine points in morphology: 



Shape (vide classification, page 131). 



Size: 



(a) Prepare cover-slip film preparations at the 

 various ages, and fix by exposure to a tem- 

 perature of 115 C. for twenty minutes in hot- 

 air oven. 



(b) Stain the preparations by Gram's method 

 (if applicable) or with dilute carbol-fuchsin, 

 and mount in the usual way. 



