CHAPTER III 



BACTERIA AND PROTOZOA 



The annus mirabilis Developments of the modern era The 

 atom Electricity Medicine Greek decadence due to 

 malaria Extension of human knowledge Mendel The 

 new romance The role of the earthworm Bacterial 

 empires in the soil Their vicissitudes Their work 

 Bacteriology and astronomy Properties of the bacterium 

 Advances in pathology The situation in botany Broad 

 generalizations Work and habits of the bacteria Prepara- 

 tion of farmyard manure Carbohydrates and proteins 

 Break-up of carbon compounds Three groups to deal with 

 proteins Value of farmyard manure Denitrifying bac- 

 teria and nitrogen fixers The protozoa. 



AN epitaph dating back to the most glorious period 

 in Athenian history has set down in terms of noble 

 simplicity the record of the great Athenians who 

 perished fighting for the country on salients of 

 offence that had been thrown out in all directions 

 into Greece and into all the barbarian hinterland. 

 The world, latinized, has since spoken of the period 

 as the annus mirabilis, and the epitaph sums up 

 grandly the stupendous blaze of energy that kindled 

 the intelligence of the world, and still acts to-day as 

 its most potent quickening force. It is open to 

 question, however, whether the Greeks ever realized 

 the astounding phenomenon in which they played 

 their part, just as it is open to question to-day 



