No. 4.] USE OF rUKE CULTURES. 1G9 



Use of Pure Cui^tures in Butter-making. 



BY PROF. F. S. COOLEY, AMHERST. 



Our time is fast making its history as a period of wonder- 

 ful discoveries. 



The inventions of the last decade in electrical appliances 

 and photoo-raphy are without precedent in the annals of the 

 race. Not less startling nor of less vital interest to us are 

 the recent discoveries in the world of microscopic life. 

 Facts lately disclosed in the study of bacteria are of mar- 

 vellous significance. 



These little plants, so minute that it is necessary for 

 thousands of them to unite to form a speck large enough 

 to be seen by the naked eye, have lately been found to 

 be involved in a vast number of functions and changes 

 of every-day occurrence. Diseases and maladies of the 

 animal body are found to be largely due to development 

 and multiplication of minute living organisms. Consump- 

 tion, diphtheria, cholera, malaria, typhus and scores of 

 other diseases have been found to be communicated and 

 caused by bacterial growth. Similar organisms on the 

 roots of certain farm crops have been found to enable them 

 to draw on the air for supplies of valuable plant food. 



Of vital interest in the living world, they seem to be of 

 at least equal importance in the world of dead organic 

 matter. As discovery extends itself, it looks as if we 

 should be able ultimately to trace every change in dead 

 organic substances to bacterial development. The putre- 

 faction of meat, the decay of vegetable matter, the fermen- 

 tations of manure, — all operate from the same causes. 

 Fermentations of beer and spirits, the souring of feed 

 stuflfs on becoming moist, the sweating of hay, result from 

 the presence of micro-organisms. The curing or sweating 



