33 



Mau tights his couuiiou diseases by resorting to the use of uiediciues, 

 especially patent medicines; he has not yet learned that diseases, like 

 weeds, may be eradicated, or that prevention is easier than cure. An in- 

 telligent farming community is apt to malie a combined attack on weeds, 

 and the less seed scattered about the fewer weeds there will be. Perhaps 

 after a time we will go after diseases as the good farmer goes after his 

 weeds; indeed, we have already reached the stage where we keep a look- 

 out for such formidable diseases as the i)lague, cholera, typhus fever and 

 several others; we do not allow them to laud. But we are so accustomed 

 to some diseases that have already landed and that have gotten a foothold 

 among us, that we seem to have forgotten that we could get rid of them 

 if we only tried. 



Among the diseases once common in civilized Europe but now becom- 

 ing more and more rare, may be mentioned leprosy, cholera, plague, typhus 

 fever, miliary fever, scurvy, smallpox, malaria, typhoid fever, and others. 

 Some countries are even beginning to show a reduction in the number of 

 deaths from tuberculosis, and some cities regard the presence of much 

 typhoid fever as a umuicipal disgrace. Man's control over the spread of 

 diseases is becoming more and more marked. 



The Analogy of Weeds and Diseases Carried Further: A botanist 

 can take his manual and check off plants, especially weeds, that are spread- 

 ing or migrating, and eonhdeutly look forward to the time when they will 

 appear in his own locality. Those who are on the lookout for new weeds 

 are rewarded every now and then by finding new arrivals. The date of 

 many arrivals is known. New weeds are introduced in impure garden 

 seed, or in the packing of crates or boxes ; some travel by rail, others by 

 water. Some come to stay for but a single season ; they may find the en- 

 vironment unfavorable, early or late frosts may be detrimental ; some live 

 for a few years and then die out ; a few, however, may find conditions 

 favorable and flourish to such an extent that they may be seen everywhere, 

 and a man who did not know of their introduction might be led to con- 

 clude that they always grew in the locality. The list of naturalized weeds 

 in our State is today quite large. 



The date of the first appearance of some of our diseases is likewise 

 known, but unless a disease has some marked or striking characteristic, it 

 is apt to be overlooked. Influenza and cholera were readily identified when 

 they arrived in our State and the date of their arrival is duly recorded. 



3— A. OF ScrENCE. 



