# Popular Science Monthly/Volume 70/March 1907/Fritz Schaudinn

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* FRITZ SCHAUDINN
By Professor THOS. H. MONTGOMERY, Jr., Ph.D.
UNIVERSITY OF TEXAS
FROM the medical and biological world a genius has been taken. and it is not saying too much to conclude that the only man of the past half century who may be considered in any way the equal of Louis Pasteur is Fritz Schaudinn. Yet when Schaudinn died, on the twenty-second of last June, he was in only his thirty-fifth year. Truly those whom the gods love die young! The work of his life is so recent that only the perspective of time can throw it out in its true proportions; but rarely has it fallen to the lot of any man to receive the quick recognition of value that has been so generally conceded to Schaudinn.
With the exception of a few contributions on the worm Ankylostomum, on bear animalcules (Tardigrades), and on bacteria, the attention of Schaudinn was devoted entirely to the Protozoa; Dujardin, Max Schultze and Schaudinn, each of these marked a great advance in our knowledge of the unicellular animals, and of them Schaudinn covered the most difficult field. For his study of the Protozoa was an intensive examination of their complex life cycles, undertaken first to elucidate their genetic relationships and the meaning of alternation of generations, and second to break a road to the checking of human diseases. His discoveries are of fundamental importance for the understanding of the genesis of the cell, particularly of the phenomena of conjugation and the reduction of the chromosomes, for our ideas of the genetic relations of the various Protozoan groups, and for the prevention of disease. It may be said that before Schaudinn entered the field almost all human infectious diseases were supposed to be due to bacteria, with the exception of the malaria parasite and certain few agents doubtfully associated with unimportant disorders. To Schaudinn more than to any other belongs the credit of the demonstration that the Protozoa are fully as efficient as the bacteria in transmitting and engendering disease. Indeed, the greatest advance in medicine of the past twenty years may be said to be just this conclusion. Schaudinn's particular merit lies in his insistence that the first step in combating any disease must be to understand the whole life cycle of the disease germ; and his genius, in his admirable and unequaled success ​in solving each complex life cycle that he undertook to investigate. All his discoveries were comprehensive and thorough, they settled the particular questions examined, and this though he selected problems the most difficult of solution. By all his training he was a zoologist, and he is a splendid instance of the fact that comprehensive results in medicine are possible only to him who has a broad biological foundation on which to build. The study of human disease is to be successful not so much by close study of human parasites only, but rather by investigation, through broad comparisons, of the animal and plant groups to which the parasites belong; in that method only is surety given.
For two years it was my privilege to work in the same room with Schaudinn as a fellow student, in the Zoologisches Institut at Berlin; accordingly, this little account of his life is as much the message of a friend as of an admirer. Of the group of students at that laboratory from 1891 on, Schaudinn was the leader from his great and rare natural modesty, as well as from his forceful character and power of tremendous application. With regard to the latter quality I well recall how on one occasion, while with exquisite ardor he was following the stages of a life cycle, he spent more than thirty uninterrupted hours at his microscope. With all his humor, his hearty laugh and his popularity, he rarely spent an evening at the Weinstube or the Bierhalle, but for his recreation took long walks into the countryside, showing a delight in every phase of nature. Perhaps the chief secret of his success was his almost intuitive ability to select the important phenomenon from the less important, and to focus his mind on that; he never allowed himself to become bewildered by the multitude of the facts, truly a rare gift.
Immediately after his death there appeared an appreciative account of his life by his old teacher, Professor Karl Heider, of Innsbrück; then a second by Professor Gary N. Calkins, of Columbia University, this printed in Science; and within the past two months more detailed biographical accounts by Professor Kichard Hertwig, of Munich, and F. W. Winter, of Frankfurt-am-Main. The last named is the most complete yet given, and was published in the Zoologischer Anzeiger, November 13; it gives a careful analysis of his various papers and labors, together with a complete bibliography.
Fritz Eichard Schaudinn was born in Röseningken in East Prussia in 1871. In the laboratory of F. E. Schulze in Berlin he commenced his investigations on Protozoa in 1892. His first years there were devoted to the investigation of free-living species, both freshwater and marine, and the rhizopods in particular. Before he made his doctorate he settled a long controversy by demonstrating that the two forms of many-chambered foraminifera, those with a large and those with a ​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 Amœba with two nuclei (Amœba binucleata) was described, and from Schaudinn dates the concept that the original cell possessed two nuclei. Then he described the copulation of the Heliozoan Actinophrys, which was the first account of reduction of the chromatin 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 foraminiferan; and his discovery of the paranucleus of Paramœba has come to greatly modify the older ideas on the genesis of the cell nucleus. These discoveries rapidly succeeded 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 parasitic protozoa, a study of particular difficulty because all such parasites live in successive different hosts. Most men have failed in these studies because they lacked the fertility and resource of Schaudinn in devising experiments. Monumental was his study on the complete life cycle of a coccidian (a sporozoan), a parasite of a centipede (Lithobius), 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 Trichosphærium. 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 Rovigno, 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 contribution to the history of Plasmodium vivax, the cause of tertian fever in man; and was the first to see the sporozoites entering living human ​blood corpuscles. The sanitary recommendations then recommended by him against malaria were adopted by the Austrian government. Further, he made observations on the biology of the mosquito that carries these protozoa. Then he worked out a blood parasite of the lizard, and discovered a Rhizopod, Leydenia, in the ascites fluid of man.
His next step was to study the parasites of the human colon, which had been called Amœba coli. Schaudinn discovered that this really is two distinct species, one of which is harmless, while the other, Entamœba histolytica, he proved to be the cause of human bloody dysentery.
His following contributions were devoted to the study of blood parasites, so-called hgemosphoridia. His initial memoir upon this subject was one of his most important. He studied the three bloodparasites of the owl, known as Proteosoma, Halteridium and Hæmamœba, which he proved to be stages of one and the same life cycle and to be flagellates and not sporozoa. Here also may be mentioned his conclusion that the organisms of human malaria are also flagellates. In connection with this study he worked out the biology of the mosquito (Culex pipiens) that infects the owl, and its mode of transference of the parasites. In his investigation of Spirochæte ziemanni he made the important discovery that the two main forms of blood flagellates, Spirochæte and Trypanosoma, are not bacteria, but flagellates, a discovery that has wonderfully clarified our knowledge of blood diseases.
In 1904 Schaudinn left Rovigno to enter the National Sanitary Commission at Berlin. He was fully recognized as the foremost investigator of Protozoan diseases, and though he had never studied medicine he became its consultant authority in Germany. Unwisely the German government for a time placed hindrances to his free initiative, and forced him to undertake certain work outside of his proper field; he had no choice but to accept these conditions, for he was a poor man with a family to support. Principles of patriotism decided him to decline a call to the professorship of protozoology recently started by the British government for the investigation of tropical diseases. At this time Schaudinn corroborated the interesting discovery of Looss, that the round worm Ankylostomum infects the mammalian host not through the mouth, but by entering the skin then being transported by the blood current to the lung, and thence to the intestine.
Perhaps what is the most important medical discovery made by him was that of 1905, when he found in the secretions of syphilitic growths a parasitic flagellate that he named Spirochæte pallida. Long had physicians searched for the cause of this disease, one of the most widespread and terrible of human disorders, and it was the crowning act of Schaudinn's life to have found it.
​Early in 1906 Schaudinn was appointed zoologist to the Institute for Ship and Tropical Diseases at Hamburg, a position that he gladly accepted, because it gave him perfect freedom for his studies and for the first time in his career an income that freed him from financial cares. But within a few months he fell a victim to intestinal abscesses, from which he had suffered for years and which he may have contracted through infection during his studies on the protozoa of the human intestine.
Most of Schaudinn's memoirs were briefly and concisely written, for he disliked to take time from his observations to put it on writing. As Richard Hertwig says of him, 'he was not a man of the writing table.' With his death, accordingly, as in the case of other great men, many of his important results have been lost to science. His descriptions are remarkable for their lucidity, as his experiments for their simplicity.
He was essentially a phylogenist, an investigator of racial history by the analysis of individual life cycles, and his achievements furnish the best possible evidence of the fruitfulness of phylogenetic study. He never called in to his aid hypothetical units, but each and every step in his conclusions was based directly upon empirical evidence; he was not a theorist, but a demonstrator. Cytology has to thank him for tracing the genesis of the centrosome, of chromosome reduction and conjugation; biology in general for demonstrating the necessity of considering the life cycle as a unit, and for having so greatly extended our knowledge of life cycles; medicine recognizes his lasting influence in the study of malaria, as the discoverer of the disease germs of dysentery and syphilis, and for pointing out the methods to follow in the study of protozoan disorders.