Highlights in the History of Microbiology 41 



venient syringe handy for the injection, he was obUged to im- 

 provise, an important necessity for those individuals who do ex- 

 tensive research. If these rods were really microbes, he hoped that 

 the mice would contract the disease and show active multiplication 

 of the organisms within the body. His improvised syringe turned 

 out to be splinters of wood, sharpened to a point, washed thoroughly, 

 and heated in a drying oven to destroy any other microbes the 

 wood might harbor. He made a small slit with a knife at the base 

 of the mouse's tail and inserted the sharpened splinter which had 

 been dipped into the blood of a recently expired sheep that had 

 been suffering from anthrax. 



After a night's sleep, which we can presume was probably not 

 too restful as he pondered over his problems, he returned to his 

 laboratory and examined the injected mice. They were all dead, 

 and at autopsy he found the internal organs and the blood to be 

 harboring these rod forms. Whereas he had injected only a few 

 microbes, there were millions of them to be seen in the dead 

 mice, an indication that active multiplication had occurred. Most 

 persons would have accepted this as conclusive proof that the rods 

 were the etiological agent in the disease. Koch, being a cautious 

 research worker, repeated his experiment over and over again, 

 transferring the blood of successive dead mice to new healthy 

 mice using his splinter technic. The results always came out the 

 same. 



At this juncture Koch hit upon an idea which was to develop 

 into a simple yet vital technic in microbiology. He wanted to 

 cultivate his suspected organisms in such a manner that he could 

 watch actual multiplication occurring before his very eyes. If he 

 could see this step in their development, he felt certain that he was 

 on safe ground if he announced that anthrax was caused bv a 

 microbe which grew and multiplied within the susceptible animals. 

 For some reason known only to Koch, he decided to place some 

 liver from an infected mouse into some fluid drained from the 

 eye of a recently slaughtered ox. We know today that such body 

 fluids are normally free of bacteria, and are an excellent culture 

 medium for growing organisms away from living hosts. 



