DEPARTMENT REPORTS. 45 



labor for the dairy bacteriologist. More particularly,' the health of tlio 

 cow, the condition of the milk in the iidder, the diseases transmitted by 

 the milker, the drainage and ventilation of the stable, the dust arising 

 from stable, bedding, and feeding, the grooming of the cow, the cleanli- 

 ness of the milker and milking utensils, the sterilization of the milk 

 utensils, the aeration of the milk, the cooling of the milk, the quality of 

 the water, the pasteurization of milk and cream, the ripening of milk and 

 cream and cheese, the manufacture of starters, and many other important 

 matters of the dairy find their rationale in germ life, in the science of 

 bacteriology, which is essential to dairy work. It is, therefore, safe to say 

 that he who has the principles of bacteriology at his finger tips is best 

 fitted to be a successful milkman or dairyman. To conduct dairy opera- 

 tions, one must be acquainted with the reasons of the different steps. 

 These, in large part, are found in knowing micro-organisms, in being 

 acquainted with the habits and the conditions under which they grow, 

 the methods of handling them and in utilizing them in the manufacture 

 of certain products. It is quite commonly the case that such knowl- 

 edge comes by rule of thumb, or otherwise, and not in an intelligible 

 form with a definite scientific basis. It is necessary that the guiding 

 principles be known in order to interpret and apply the knowledge to 

 the best advantage. 



SOIL BACTERIOLOGY. 



Chemistry tells us about some of the elements of the soil; physics 

 tells us of its physical structure and its dynamic forces; but it remains 

 for bacteriology to consider those agents which produce those peculiar 

 changes in soil, by which the latent forces are rendered active; those 

 agents which create food substances for plants, and, in short, those 

 agents which make soil fertility. Bacteriology stands for the changes; 

 chemistry measures the changes; and physics fosters the changes which 

 we find taking place through the fermentations wrought by the activity 

 of micro-organisms. What does soil bacteriology mean, accordingly? 



We are familiar with the knowledge furnished us by geologists that 

 soil usually results from rock disintegration, and that its fertility is 

 measured by the amount of those constituents required for plant growth 

 or of organic matter which it contains and the possibility of a dissolu- 

 tion of this organic matter. Through the instrumentality of micro- 

 organisms, through chemical interchange, and through physical treat- 

 ment, we find soil made ready for plant growth. There are those who 

 believe that no unimportant part of the work is due to microbian action, 

 This conclusion is reached from a knowledge of fermentations in general, 

 •and of those taking place in the soil, for practically all organic reduc- 

 tion must be attributed to micro-organisms; practically all fermenta- 

 tions of whatever nature also go to this source; and inasmuch as we 

 know that organic matter is not suitable for plant growth and that 

 much inorganic matter must be made soluble, it follows that plants 

 are dependent for their food preparation from organic substances and 

 from insoluble inorganic substances by the growth and development of 

 microbes. They reduce the more complex substances to simpler forms, 

 and frequently render soluble, insoluble inorganic substances in which 

 the plants find food. So it is that much of the manurial value of those 

 materials which are used upon lands is derived through living forms 



