10 PROTOZOOLOGY 



infusions in which no Infusoria developed without exposure to the 

 atmosphere. This experiment confirmed that of Redi who, twenty 

 years before, had made his well-known experiments by excluding 

 flies from meat. Joblot illustrated, according to Woodruff (1937), 

 Paramecium, the slipper animalcule, with the first identifiable 

 figure. Trembly (1715) studied division in some ciliates, including 

 probably Paramecium, which generic name was coined by Hill in 

 1752. Noctiluca was first described by Baker (1753). 



Rosel (1755) observed an amoeba, possibly Amoeba proteus 

 or an allied form, which he called "der kleine Proteus," and also 

 Vorticella, Stentor, and Volvox. Ledermiiller is said to have 

 coined the term "Infusoria" in 1763 (Biitschli). By using the 

 juice of geranium, Ellis (1770) caused the extrusion of the 'fins' 

 (trichocysts) in Paramecium. Eichhorn (1783) observed the helio- 

 zoan, Actinosphaerium, which now bears his name. O. F. Miiller 

 described Ceratium a little later and published two works on the 

 Infusoria (1786). Although he included unavoidably some Meta- 

 zoa and Protophyta in his monographs, some of his descriptions 

 and figures of Ciliata were so well done that they are of value 

 even at the present time. 



At the beginning of the nineteenth century the cyclosis in 

 Paramecium was brought to light by Gruithuisen. Goldfuss 

 (1817) coined the term "Protozoa," including in it the coelente- 

 rates. Ten years later there appeared d'Orbigny's systematic 

 study of the Foraminifera, which he considered as microscopical 

 cephalopods. In 1828 Ehrenberg began publishing his observa- 

 tions on Protozoa and 1838 he summarized his contributions in 

 Die Infusionsthierchen als vollkommene Organismen, in which he 

 diagnosed genera and species so well that many of them still hold 

 good. Ehrenberg excluded Rotatoria and Cercaria from Infu- 

 soria. Through the studies of Ehrenberg the number of known 

 Protozoa increased greatly; he, however, proposed the term 

 "Polygastricha," under which he placed Mastigophora, Rhizo- 

 poda, Ciliata, Suctoria, desmids, etc., since he believed that the 

 food vacuoles present in them were stomachs. This hypothesis 

 became immediately the center of controversy, which inciden- 

 tally, together with the then-propounded cell theory and improve- 

 ments in microscopy, stimulated researches on Protozoa. 



Dujardin (1835) took pains in studying the protoplasm of 

 various Protozoa and found it ahke in all. He named it "sarcode." 



