SYNOPSIS 



INTRODUCTION 

 CHAPTER I 



THE SCOPE OF THE ENQUIRY 



DEFINITION OF TERMS. Transmutation not evolution evolution in bac- 

 teria its stages. Natural variation "Spontaneous" and "impressed." Varia- 

 tion easily studied in bacteria unicellular organisms method of generation 

 rapidity of generation environment easily modified. Natural selection. 

 Artificial selection. "Transmutation of Species" apparently contradictory 

 meaning of "species" based on characters. Arbitrary nature of distinction 

 between species illustrated by streptococci classified according to food- 

 stuffs and haemolytic power, adhesiveness, staining, cultural characters, 

 virulence and pathogenicity, agglutination, fermenting power. "Species" 

 not a rigid term. 



A CONSIDERATION OF THE POSSIBILITIES. 1. Simple variation. 2. Varia- 

 tions in different directions associated. 3. Development of intermediate 

 forms. 4. Slight changes in closely allied organisms. 5. Complete change in 

 characters. (Pages 3 12) 



CHAPTER II 



CONDITIONS MODIFYING THE CHARACTERS OF BACTERIA 



1. Spontaneous variations. Pleomorphism. Unexplained variations. 

 2. Geographical distribution. 3. Prolonged cultivation extends survey 

 permits natural selection influence of saprophytism. 4. Conditions of culti- 

 vation, (a) lowered vitality, (6) crowding of colonies, (c) temperature, (d) at- 

 mospheric pressure, (e) oxygen, (/) sunlight. 5. Ultra violet rays. 6. Elec- 

 trolysis. 7. Age of culture pleomorphism other variations. 8. Culture 

 medium (a) age of medium, (&) reaction of medium, (c) nature of medium 

 natural secretions pathological exudations water, (d) chemical sub- 

 stancescarbolic acid, antiseptics, boric acid, potassium bichromate, sodium 

 benzoate, glycerine, iodine trichloride, lactic acid. 9. Prolonged contact 

 with particular foodstuff. 10. Artificial selection method sometimes in- 

 effective. 11. Symbiosis lichens nitrifying organisms parasitism anaer- 

 obes. Symbiosis may confer new powers may have no effect. Methods of 

 studying symbiosis mixed growth, adjacent colonies, criss-cross planting, 

 surface and deep growths, double celluloid sac, successive growth. 12. Para- 

 sitism, (a) transmission through alimentary canal, (6) passage, (c) celioidin 

 sac in body cavity, (d) residence in living tissues, (e) during disease, (/) in 

 "carriers." (1327) 



