144 CLASSIFICATION OF THE MICRO-ORGANISMS. 



the monadina thus form" so-called zoocysts in contrast to 

 the sporocysts in which resting spores develop (Zopf). 



The more highly organised mycetozoa obtain their 

 nourishment entirely from dead organic materials, 

 chiefly vegetable, more rarely animal. A large amount 

 of moisture is a necessary condition for their develop- 

 Parasitic ment. The lower mycetozoa, on the other hand, play an 

 oa " important part as parasites. They chiefly attack aquatic 

 plants, alga3, fungi, &c., and in consequence of their 

 rapid development and the ease with which their germs 

 can spread the diseases of the algae caused by them have 

 often an epidemic character. But they seem also to be 

 able to act as parasites on higher plants as well as in 

 the animal body. Animals which seek their food in 

 marsh water and in mud seem to be most readily 

 affected. In the intestine of man also amoebae have 

 been found, but their characteristics are not accurately 

 known. It is therefore very readily conceivable that the 

 monadina, which it would be very difficult to recognise 

 in the animal body, may deserve marked attention from 

 a hygienic standpoint on account of their role as 

 infective agents. 



Forthe present only 2 monadinoe need be specially mentioned. 



1. Plasmiodopliora, brassicds. This organism lives as a 

 parasite in the roots of cruciferae, especially in certain 

 varieties of cabbage, and causes marked swelling at the part. 

 Large cells with amoeboid movements are found in the 

 markedly enlarged cells of the roots, these ultimately become 

 motionless and divide into a large number of spores, without 

 previously forming a special membrane. A ciliated swarming 

 spore escapes from the spore into the water, and eventually 

 penetrates through the young epidermis of the root into a- 

 new host. 



2. Haplococcus reticulatus. This organism has been fre- 

 quently found by Zopf in the muscles of swine. It forms 

 zoocysts 1622 /* in diameter, almost spherical, with smooth 

 membranes. In these 6 15 amoebae arc formed at the period of 

 ripening, and these pass out of thin and ultimately completely 

 gelatinous places in the membrane. The spores have the form 

 of spheres, or tetrahedra, with markedly rounded surfaces and 

 borders, and a diameter of 25 30 /* ; on the surface there are 

 often band-like elevations. In the contents of the ripe spore 

 there is a large drop of reserve plasma. The mode of sprout- 



