830 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



mentality, red blotches on the skin, and enlargement of the lymphatic 

 glands, are all early signs of the disease. In the later stages, headache, 

 mania, uncontrollable sleep, and other nervous symptoms may be 

 present. Death rarely results froin trypanosomiasis alone; the patients 

 usually succumb to one of the secondary infections, to which their 

 reduced condition makes them especially Uable. No toxin has been 

 isolated in trypanosomiasis, but from the nature of the infection no 

 great amount would be necessary to produce symptoms. The para- 

 sites not only live in the blood and other fluids of the body 

 but are found in the tissues of various organs. They are distributed 

 throughout the tissue of the brain and their presence is associated 

 with infiltration of the tissue about the blood-vessels with large 

 numbers of lymphocytes. 



The xecbgnition of trypanosomiasis depends upon the demonstra- 

 tion of the parasites. They may be found in fresh or stained prepara- 

 tions of the blood, in the juice obtained by aspirating an enlarged 

 l5anphatic gland, or in the cerebrospinal fluid. The examination of the 

 blood is the simplest method of searching for. trypanosomes; the 



■ examination of gland juice is the most efficient one. 



The improvement in the methods of treating trypanosomiasis during 

 the past ten years (1901-1911) affords an excellent example of the value 

 of laboratory work. Before igoi arsenic, given in some inorganic form, 

 was the only drug known to have any effect on trypanosomiasis, f nor- 

 ganic arsenic drives the parasites from the blood and improves the 

 patient's condition. Unfortunately, the trjrpanosomes usually reap- 

 pear and, then, they have become resistant to arsenic so that the patient 

 succumbs in spite of repeated doses of the drug. Many organic com- 

 pounds of arsenic were experimented with in the hope of finding an 

 efficient tr3^anocide and several valuable drugs have been found: 

 "Atoxyl" which is the sodium salt of para-amido-phenyl-arsenic acid, 

 acetylated atoxyl, and arsenophenylglycin, are all organic compounds of 

 arsenic. They are much more effective than is arsenic itself. Similar 

 organic compounds of antimony and tartar emetic are almost as 



, effective, while certain aniUne dyes have a distinct trypanocidal value. 

 It has been found that trypanosomes may become resistant to any one 

 of these drugs, and that drugs may destroy some stages of the trypano- 

 some while they are unable to destroy others. In order to give the 

 parasites no opportunity of acquiring resistance to any drug, and in 



