1883.] THE VENTILATION OF FARM BUILDINGS. 199 



putrescent fluids, especially in blood and urine, and also in the 

 blood of animals having certain diseases. They vary in size as 

 well as in form, some requiring the highest powers of the micro- 

 scope to define them. Sanitary science has made vast strides in 

 the last two decades, largely due to the investigations and experi- 

 ments in connection with these infinitesimal bodies. They have 

 been propagated by placing them in a proper nidus, such as a slice 

 of apple, water and milk, water and blood, or water and urine, and 

 have been thus bred for several generations, and finally the animal 

 system inoculated with them, producing the true form of the 

 disease that they are charged with originating. 



In the last few years it has been claimed that the various specific 

 diseases are caused by different species of bacteria, and to some ex- 

 tent this has been demonstrated. This is instanced in the swine 

 plague of which we have heard so much, and which has been so 

 ably reported by Dr. J. H. Detmers of Chicago, who conducted his 

 investigations under government auspices, for a full reading of 

 which I will refer you to his report to the Commissioner of Agri- 

 culture in 1880. The result of some of his experiments showed 

 " that an inoculation with bacilli and bacillus germs, cultivated in 

 so innocent a fluid as milk, will produce the disease with just aS 

 much certainty as an inoculation with the pulmonial exudation from 

 a diseased or dead hog." It appears also from the experiments of 

 Dr. Detmers, and they have been fully confirmed by Dr. Law of the 

 Cornell University, that the special contagion of swine plague may 

 be communicated to other animals. 



"Why have I called your attention to this special subject ? It is 

 this: These minute bodies are capable of self -multiplication, and 

 within a very limited space of time, and being so marvelously 

 small and light, they are taken up by the slightest currents and 

 mingled with the atmosphere. If the air is dry and pure they soon 

 perish. In pure air charged with watery vapor, such as is given 

 ofE by animal respiration, they live for a length of time undeter- 

 mined; but in humid air, charged with putrid animal matter, they 

 live, nourish themselves, and acquire the full vigor of their nature. 

 It is not necessary to inoculate an animal with them, for when they 

 exist in the air they will find their- way into the fluids of the body, 

 through abrasions of the skin or mucous surface, or by being drawn 

 into the lungs themselves. All classes of animals may receive them ; 



