550 THE HISTORY OF BIOLOGY 



ravaged by that disease; by excluding the mosquitoes from human dwellings 

 and eradicating their larvae, he has succeeded in making inhabitable dis- 

 tricts that were formerly dangerous to live in, and, further, his exhaustive 

 studies of the biology of the malarial mosquito have made it possible for 

 other countries also to take energetic measures for its extermination. 



A number of other parasites have latterly been discovered and described, 

 as, for example, the Flagellata, which produce in tropical Africa the fatal 

 sleeping-sickness, which is transmitted from one person to another by the 

 tick; and, further, the producer of the cattle-plague, also an African disease, 

 transmitted by the tsetse-fly, which had made cattle-breeding impossible in 

 extensive districts. These parasites were specially studied by Koch and his 

 pupils. 



To the beginning of our century belongs the discovery of Spirockate 

 pallida, the carrier of syphilitic infections, one of the most dangerous ene- 

 mies of man. It was discovered by Fritz Schaudinn, who has thereby en- 

 sured for himself a place in the cultural history of the world. Born in 1871 

 in East Prussia, he studied at Berlin, and after taking his doctor's degree 

 he was given an appointment at the Gesundheitsamt. Labouring under con- 

 stant difficulties and in frequent dispute with the old despotic Koch and other 

 bureaucrats in the Civil Service, who neither would nor could appreciate the 

 value of his ideas, he worked his way up to a brilliant reputation as a micro- 

 biologist. It was not until shortly before his death that he received the per- 

 manent post worthy of him as head of a research institute at Hamburg. He 

 made valuable contributions to our knowledge of the life of the malarial 

 parasite; by means of experiments upon himself he studied the dangerous 

 Amceba histolytica, the producer of a serious form of intestinal catarrh — an 

 experiment that cost him his life. He also published the valuable results of 

 his researches into the reproduction of the Foraminifera and Heliozoa. The 

 above-mentioned discovery of Spirochate pallida he made in the year before 

 he died. Moreover, he had a number of distinguished pupils, as, for instance, 

 M. Hartmann, born in 1876, who took up for further study his theoretical 

 research-work on the Protozoa, and S. Prowazek (1875-1916), who con- 

 tinued his work on the disease-producing Sporozoa. 



4. Vegetable Morphology 



Development from romanticism to exact investigation 

 It is necessary to take a brief glance at the method of morphological re- 

 search as applied in the sphere of botany, especially in view of the part 

 played by plants as a basis for modern evolutional theories. For this pur- 

 pose we must go back to the period before the appearance of Darwinism, 



