INTRODUCTORY HISTORICAL REVIEW 21 



succeeded in producing the disease in healthy horses and dogs by 

 inoculating the blood in which he had seen these organisms. Steele 

 confirmed Evans' observations, and named this pathogenic organism 

 Spirocheta Evansii. It is now known as Trypanosoma Evansii, 

 and was the first pathogenic trypanosome to be discovered. In 

 1882 Laveran discovered the plasmodium malariae, and early in the 

 next decade Theobald Smith discovered the protozoon piroplasma 

 bigeminum as the cause of Texas fever. 



Since the fundamental work of Pasteur and Robert Koch, studies 

 of pathogenic microorganisms in general and of pathogenic bacteria 

 in particular have been placed on a firm basis, and have assumed 

 the greatest importance in the theory and practice of human and 

 veterinary medicine. 



