BACTERIOLOGY IN A NUTSHELL. 



slake their thirst in infected pools in swamps 

 and then alighting on healthy bodies they com- 

 municate to them the disease-producers by 

 inoculation. Grassi, Bignami and other Italian 

 workers have proven by their experiments that 

 the theory of Koch of Germany and of other in- 

 vestigators in Europe and America in this 

 regard is based upon fact. They also teach that 

 these mosquitoes carry the poison in the same 

 way from the sick to the well. Prevention of 

 malaria is only possible by destroying the 

 mosquitoes. 



Uncinariasis^ another disease caused by an 

 animal parasite, the uncinaria duodenalis, is 

 quite common in the United States as well as 

 in other parts of the world, and is often 

 diagnosed as malaria, some of the symptoms 

 being similar. The seat of invasion in un- 

 cinariasis is the duodenum, the jejunum and 

 less frequently the colon. Other names given 

 to uncinariasis are hook-worm disease, anchylo- 

 ostomiasis, Egyptian chlorosis, etc. Hook- 

 worm disease is its common title. This 

 name has probably arisen because of the 

 peculiar bending backward upon itself of the 

 anterior portion of the parasite, giving to it a 

 hook-like appearance when observed under the 

 microscope. The germs of uncinariasis are 

 blood devourers and by means of peculiar tooth- 

 like and suction appendages they cling to the 

 94 



