524 MISCELLANEOUS FARM SUBJECTS 



presence of harmful germs in the intestines. He also discovered 

 that lactic ferments largely destroy such harmful germs. Boiled 

 water, cooked meats and stewed fruits contain lactic ferments. He 

 is also the father of the doctrine that appendicitis is produced by 

 email intestinal worms, and he developed a serum to combat the dis- 

 ease. He was the assistant to Dr. Koch in discovering the cause and 

 cure of sleeping sickness. Prof. Emil Behring discovered an anti- 

 toxin for diphtheria, and claims to have found a cure for tuberculosis. 

 He claims to be able to wholly eradicate the disease in its earlier 

 stages, and to arrest it after it has been well started. He calls his dis- 

 covery a curative principle. Prof. Ehrlick discovered the manner in 

 which the animal body is able to produce antitoxins. He also dis- 

 covered a cure for diseases of the blood, and arseno-phenyl-glycin, a 

 bright yellow powder, a cure for sleeping sickness. 



By discovering a method for artificially coloring bacteria, Dr. 

 Koch made a great advance in the identification of germs. He has 

 also devoted much study to tuberculosis and cholera. He spent 

 eighteen months in Africa studying the sleeping sickness and found 

 that tsetse flies carried the disease germs from crocodiles and hippo- 

 potami. The discoveries in bacteria in the human system led to a 

 study of bacteria in plants and in the soil and their effect on plant 

 life. This study has already resulted in some discoveries that are 

 destined to prove of inestimable value to agriculturists. 



Plants and Plant Food. Plants are composed of the elements 

 carbon, hydrogen, oxygen and nitrogen together with other ele- 

 ments. Of these the first three are furnished in the carbonic acid gas 

 present in the air and in the soil water. The fourth element, nitro- 

 gen, is one of the gases of the atmosphere and is therefore abundant- 

 ly supplied to such plants as are capable of utilizing it. For their 

 growth plants must have these elements supplied in their food in 

 some available form. All plants must have nitrogen. 



Nitrates can be artificially supplied to growing crops as a com- 

 mercial salt-like nitrate of soda. Within the soil nitrates are being 

 elaborated on a large scale ou* o^ the nitrogenous organic matter of 

 the soil through the agency of soil bacteria. Rain will supply from 

 1.75 to 3.75 pounds of nitrogen per acre per annum as nitric acid 

 and as ammonia, but this amount is totally insufficient to meet the 

 demands of growing crops and this deficiency must be supplied by 

 other means. This is done by means of bacteria in the soil or plant. 

 (Del. Col. B. 40.) 



What Are Bacteria? Bacteria are plants. Although they were 

 formerly classed as animals, it is now universally conceded that they 

 ere plants. They are single-celled and of simple structure, being 

 composed almost entirely of protoplasm; they differ from higher 

 plants in that they contain no chlorophyl (green coloring matter). 

 They resemble more closely the yeasts and molds. There are many 

 different varieties of bacteria; about 1,200 different kinds have been 

 isolated and studied, and new varieties are being found every day. 

 Bacteria are very small, being invisible to the naked eye. It would 

 take about 10,000 average-sized bacteria placed end to end to make 



