Johannes Holtfreter Papers

Johannes Holtfreter was a 20th Century German-American developmental biologist who was famous for his work in the subject of embryology, specifically for his work with amphibian embryos. In the midst of his early career, World War II tensions were rising, and knowing he was being spied upon and fearing he would be caught by the Nazi regime, Johannes escaped to England. Once in England, he, along with other German refugees, were sent to Canada to an Internment Camp in order to escape the inevitable Nazi invasion in England. In 1942, after two long years in a Canadian Internment Camp, Johannes received a fellowship at McGill University in Canada which allowed him to continue his studies within the field of embryology, particularly on the subject of gastrulation in cells. After his time at McGill University, Johannes accepted an assistant professorship at the University of Rochester where he finished out his career as an associate professor in 1969.

Johannes Holtfreter is most known for his work in developing a salt solution, called Holtfreter’s Medium (or Holtfreter’s Solution) that helped to keep developing amphibian embryos alive and healthy while under scientific observation. As part of implementing the use of this salt solution, Holtfreter created best practice procedures for handling embryos under observation, which helped to reduce cases of bacterial contamination that were common at the time. He is also well-known for his studies of dead organizer tissue in relation to its inductive properties, which included applying Spemann-Mangold’s Organizer, which focused on cells that are responsible for the development of the nervous system within amphibian embryos. His focus on amphibian development resulted in collaborations with prominent scientists in the field, including Viktor Hamburger, Hans Spemann, and Hilde Mangold, and resulted in his induction into the National Academy of Sciences.