Spermism was one of two models of preformationism, a theory of embryo generation prevalent in the late seventeenth through the end of the eighteenth century. Spermist preformationism was the belief that offspring develop ...

The term homunculus is Latin for "little man." It is used in neurology today to describe the map in the brain of sensory neurons in each part of the body (the somatosensory homunculus). An early use of the word was in the ...

Frederik Ruysch, working in the Netherlands, introduced the term epithelia in the third volume of his Thesaurus Anatomicus in 1703. Ruysch created the term from the Greek epi, which means on top of, and thele, which means ...

Ovism was one of two models of preformationism, a theory of generation prevalent in the late seventeenth through the end of the eighteenth century. Contrary to the competing theory of epigenesis (gradual emergence of form), ...

In 1914 Albert Niemann, a German pediatrician who primarily studied infant metabolism, published a description of an Ashkenazi Jewish infant with jaundice, nervous system and brain impairments, swollen lymph nodes ...

The sex of a reptile embryo partly results from the production of sex hormones during development, and one process to produce those hormones depends on the temperature of the embryo's environment. The production of sex ...

Wilhelm Johannsen in Denmark first proposed the distinction between genotype and phenotype in the study of heredity in 1909. This distinction is between the hereditary dispositions of organisms (their genotypes) and the ...

Historically the exact age of human embryo specimens has long perplexed embryologists. With the menstrual history of the mother often unknown or not exact, and the premenstrual and postmenstrual phases varying considerably ...

Isotretinoin is a molecule and a byproduct (metabolite) of vitamin A, and in greater than normal amounts in pregnant women, it can cause fetal abnormalities including cleft lips, ear and eye defects, and mental retardation. ...

In 1868 in England, Charles Darwin proposed his pangenesis theory to describe the units of inheritance between parents and offspring and the processes by which those units control development in offspring. Darwin coined ...