264 STATE HORTICULTURAL SOCIETY. 



and the difficulty of destroying them by ordinary disinfecting methods fur- 

 nished a simple explanation of the cases in which the disease had apparently 

 appeared spontaneously. The development of spores has now been observed 

 in nearly all species, and it must be looked upon as a common mode of repro- 

 duction. 



The same year Pasteur published his researches on the diseases of beer and 

 cleared up many obscure points in the process of fermentation. 



The year 1877 marks an epoch in agricultural science from the discovery of 

 the microbes of soil nitrification by Schloessing and Muntz, as they furnish a 

 ready solution of many of the obscure problems in farm economy. Our 

 knowledge of the germs of disease was materially extended by Pasteur's 

 investigation of chicken cholera published in 1878. 



As an illustration of the perfection of methods of microscopic manipulation 

 we should not omit to mention, as one of the achievements of the same year, 

 the success of Dr. Dallinger in measuring the flagellum of bacterium termo 

 (or the microbe of putrefaction), which he found to be 1-200,000 of an inch 

 in diameter. 



The most striking discovery in 1879 was made by Pasteur, who found that 

 the bacillus of anthrax could be restrained in its activity to produce a mild 

 form of the disease, by inoculation, that proved to be a protection against the 

 subsequent occurrence of the disease, even after inoculation with the strongest 

 virus. The " attenuation of virus " and protective inoculation is now practiced 

 in many other diseases. 



In 1880 Prof. Burrell discovered a microbe, which he proved to be the cause 

 of pear blight, and he communicated the disease to healthy trees by inocula- 

 tion. 



We must close this brief outline of the progressive development of our 

 knowledge of microbes and the important role they perforin in the economy of 

 nature, with the mere mention of the discovery by Koch of the bacillus of 

 tuberculosis in 1882, as since that time the literature of the subject is too 

 voluminous for discussion in a popular lecture. 



The germ theory of contagious diseases has been so clearly demonstrated 

 in such a large number of cases that it seems to be a legitimate inference that 

 all communicable diseases are probably caused by specific living organisms. 



The great value of this theory, from a sanitary point of view, can hardly be 

 over-estimated, as we now have something tangible to study in the phenomena 

 of contagion and epidemics, and can trace their specific causes to their original 

 source. 



This world of microscopic forms and its unequivocal influence for good or ill 

 upon the higher planes of animal and plant life, presents a field for investiga- 

 tion of exciting interest. From the peculiar methods of manipulation and the 

 special training required in original researches in this field a new department 

 of science must be recognized and provided for in our industrial schools, if the 

 full benefits of applied science are to be realized. 



Agriculture must now be studied from the standpoint of this new science to 

 determine the relations of microscopic organisms to every process and interest 

 of tne farm. The best results with the higher forms of life which we have to 

 deal with in our farm crops and animals, can only be obtained when we are 

 able to trace their true relations to this lower plane of life on which they are 

 dependent for their well-being and existence. 



Aside from the direct benefits arising from the useful knowledge acquired, 

 the study of this department of science is entitled to attention as an educa- 



