276 POPULAR SCIENCE MONTHLY 



small embryonal chamber, represent different stages in the same life 

 history. He elucidated the life cycle of Calcituba, and discovered in 

 it a simple and probably very primitive mode of cell division. The 

 division of the Amoeba with two nuclei (Amoeba binucleata) was de- 

 scribed, and from Schaudinn dates the concept that the original cell 

 possessed two nuclei. Then he described the copulation of the Helio- 

 zoan Actinoplirys, which was the first account of reduction of the chro- 

 matin and caryogamy of any protozoan, compared the processes here 

 with the similar ones in the many-celled animals, and showed that the 

 central granule acted as a centrosome. Conjugation of the spores was 

 also discovered in Hyalopus, a f oraminif eran ; and his discovery of the 

 paranucleus of Paramceba has come to greatly modify the older ideas 

 on the genesis of the cell nucleus. These discoveries rapidly suc- 

 ceeded each other, marked a great advance over all preceding studies 

 on the reproduction phenomena of the protozoa, and stimulated others 

 to the same field of study. 



Next he turned himself to the analysis of the life cycles of para- 

 sitic protozoa, a study of particular difficulty because all such parasites 

 live in successive different hosts. Most men have failed in these stud- 

 ies because they lacked the fertility and resource of Schaudinn in de- 

 vising experiments. Monumental was his study on the complete life 

 cycle of a coccidian (a sporozoan), a parasite of a centipede (Litho- 

 bius), made in conjunction with Siedlecki. This gave for the first 

 time the complete history of any sporozoan, and was soon followed 

 by an equally conclusive and thorough research, extending through 

 five years, of the life cycle of Trichosphcerium. These are classics in 

 the study of the protozoa, and they showed the method by which results 

 are to be reached in the search of the parasites of human disorders. 

 In each of these life cycles there follow upon each other a long line 

 of generations, with great dissimilarity of the successive generations; 

 Schaudinn drove home the conclusion that the unit of study should 

 be the whole life cycle, and his results rendered it probable that many 

 forms of protozoa that had hitherto been regarded as different species 

 might be merely stages of one and the same life cycle. This was one 

 of his major contributions that guided him in his later work and has 

 caused an entire change in progressive medicine. 



Schaudinn then left Berlin to become director of the laboratory 

 at Eovigno, on the Adriatic Sea, whither he was called primarily 

 to contribute to the study of the malaria organisms. There he first 

 worked out the life history of Cyclospora, the agent of enteritis of the 

 mole, carrying out his method to approach human disorders from a 

 preliminary broad comparative basis. Then he made a valuable contri- 

 bution to the history of Plasmodium vivax, the cause of tertian fever 

 in man; and was the first to see the sporozoites entering living human 



