FUTURE WORK 27 



in the fight against yellow fever. Dr. Lazear, an American army 

 surgeon, allowed himself to be bitten by a mosquito in an infected 

 ward. He soon acquired yellow fever in the most terrible form and 

 died a martyr to science and a true hero. He gave up his life for 

 others; the plain record of his sacrifice is recorded thus upon a 

 tablet erected to his memory: "With more than the courage and 

 devotion of the soldier, he risked and lost his life to show how a 

 fearful pestilence is communicated and how its ravages may be 

 prevented." That this is conveyed only by the bite of the mosquito 

 was shown by the following: Three brave men slept for twenty 

 nights in a small, ill-ventilated room screened from mosquitoes but 

 containing furniture and clothing smeared with the excretion of 

 yellow fever patients some of whom had died of the disease. None 

 of the men contracted yellow fever, thus indicating the disease was 

 not of a contagious nature. 



Agricultural Bacteriology. In 1883 Burrill, by the discovery -of 

 the organism which causes fire- or pear-blight, opened up a similar 

 interesting and practical field in the plant kingdom which even at 

 the present day is only in its infancy. 



It may appear from the preceding that bacteria are all enemies 

 of man, but this is not true, for there are many more beneficial 

 bacteria than injurious ones. 



Even in the field of agricultural bacteriology rapid advances have 

 been and are being made. To Beijerinck, Hellriegel, Wilfarth, Lip- 

 man, and a host of others, we owe our knowledge concerning the 

 morphology and physiology of the nitrogen-fixing organisms. In 1888 

 Winogradsky isolated the nitrifying organisms which grow on a 

 medium devoid of all organic matter and since that time there is an 

 ever-increasing volume of work on this phase of the subject. Han- 

 sen's investigation in industrial fermentation is also important. 



Future Work. One may think from the preceding that in this 

 field of science there is little to be done, but this is not the case, for 

 there are diseases still unconquered. The great u White Plague" 

 still claims its millions each year. There are diseases which are 

 sapping the very life-blood of the nation, yet they go unchecked. 

 Science as yet has not come to the aid of the unfortunate victims. 



As regards the beneficial organism w r e have only just started to 

 realize their great possibilities. In the soil are five great classes of 

 organisms which deal with the transformation of nitrogen. One 

 class carries on putrefaction, changing the insoluble proteins into 

 ammonia, another picks the ammonia up as formed, transforming 

 it into nitrites, and even this must be changed into nitrates before 

 plants can use it. Under what condition are these changes carried 

 on at a maximum rate? What influence has moisture, temperature 

 crop, and method of tillage on this change? Some of these questions 

 are being answered by the work now being conducted, but there are 



