522 CHAPTER 67. 



The only i-ecognised specific diseases affecting the horse are Anthrax, 

 Influenza, Glanders, Farcy, and Pink Eye. Ophthalmia, sometimes called 

 " specific " in contradistinction to other less serious affections of the eye, 

 is a true specific disease. 



2nd. Non-specific diseases, i. e. diseases of spontaneous growth, such as 

 constitutional disturbance in the lungs, liver, stomach, and other organs. 



1046. 0/ Specific Diseases. 



So far as we can surmise, for positive knowledge has not been vouch- 

 safed to us, the germs or organisms, from which Specific diseases are 

 developed, are aboriginal creations. 



It will probably be admitted that each seed or herb bearing seed after 

 its kind is an aboriginal creation. No wheat can grow except from a 

 wheat seed. ~Ko oak can grow unless there is an acorn. 



Similarly no Specific disease can be reproduced, unless there is a germ 

 of that disease present. 



No amount of suitable manure mixed with suitable soil will produce an 

 oak, unless the germ of an oak exists in that soil. 



Similarly no amount of malaria or " nidus " suitable for the develop- 

 ment of a specific disease \\'ill produce that disease, unless the germ of 

 the disease is in the nidus. 



If the germ of an oak is in suitable soil, it will under favorable climatic 

 influences develop into an oak. If the climatic conditions are unfavor- 

 able it will not develop into an oak, even though the soil is suitable. 



Similarly, if the germ of a specific disease is present in a suitable 

 malarious nidus, it will under circumstances favorable to its germination 

 develop into that Specific disease. If, on the other hand, circvmistances 

 are unsuitable to its development, it will lie dormant. 



To take a well-known instance. Let us substitute " seed " for " germ." 

 The Wheat seed found among the mummies of Egypt germinated freely 

 after a lapse of 3000 years, when placed in a suitable soil and under 

 favorable climatic influences ; but its vitality had lain dormant until it 

 found a suitable seed bed. 



Similarly germs of disease may lie dormant for any number of years ; 

 and, so far as we know, or rather can surmise, their vitality is not 

 destroyed by any lapse of years. 



1047. Of Germs of Disease. 



What is the germ of each specific disease 1 We do not know. Wherein 

 lies the scent of flowers 1 AVe do not know. In regard to seeds and 

 their produce it is somewhat different. We can see and handle seeds. 

 We cannot handle the germs of disease, but in one or two instances it is 

 possible to see them, and even to watch their growth with the aid of the 

 microscope. We only know or at least believe from the reproduction of 

 specific disease that the germs of those diseases must exist. 



Seeds may lie dormant and produce no crop for any length of time. 



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