202 B. GRASSI, 



number of zoosporoid bodies and sometimes smaller number of 

 other infusorial forms of various kinds. After prolonged study 

 of the zoospores under various circumstance, I ara unable to in- 

 dicate any Constant differences to distinguisi! them from those of 

 human excreta. „ 



Questi sono i fenomeni che si osservano nelle vaccine, tenute 

 in una camera umida: 



" Again and again we find a basis abounding with zoospores: 

 increase in the numbers of these bodies for some time; a ces- 

 sation in their activity ; the appearance of multitudes of bodies 

 agreeing in size and form with the inactives zoospores, but cha- 

 racterised by the presence of a contractile vesicle; the emer- 

 gence and growth of these, as active amoeboid bodies and the 

 appearence of sporangia ... Ali that can be positively affirmed 

 is that the amoeboid bodies which replace the zoospores prima- 

 rìly present appear to be directly derived from the latter and 

 that the two forms seem merely to represent different deve- 

 lopemental stages of one and the same organism, connected with 

 one another by the intervention of an inactive stage . . . After 

 continuing to progress through the medium for variable periods, 

 the Amoebae either cease to move, and remaining more or less 

 isolated, become encysted, or becoming aggregated into masses 

 give origin to sporangia... The encysted bodies are either quite 

 free or are associated in little groups and knots. As a rule, no 

 further change appears, to occur within them and they remain 

 unchanged for indefinite periods, ready to resumé activity when 

 favorable conditions again present themselves. In place of be- 

 coming encysted, however, we normally find the Amoebae, after 

 some time become more sluggish in their movements, and adhe- 

 ring to one another in pairs or groups of various sizes, the union 

 becoming very intimate, and in some cases proceeding to such 

 a degree of apparent fusion that we are only able to estimate 

 the number of individuai elements entering into the formation 

 of a group by the number of nuclei or of rigidly dilated con- 

 tractile vesicles which may persist . . . „ Si possono trovare 



