“Can breast feeding help you in later life? Evidence from German military heights in the early 20th century”

Considerable literature exists on the benefits of breast feeding on the health and survival of infants and young children, but there is less on the effects on later life outcomes. One such measure of health and well-being that has received attention in the historical literature is terminal adult stature. Information on height is rather widely available; however, it is much more difficult to obtain data on breast feeding. One country that does have such information is Imperial Germany (1871-1919). A number of physicians and local health officials collected information on the incidence and duration of breast feeding early in the 20th century, particularly because of concern about the unusually high infant mortality rates in parts of Germany. Hallie Kintner has surveyed the published results of these studies. The information on the prevalence of breast feeding for the period 1903/10 has been inputed into a database of demographic and economic variables for the counties (Regierungsbezirke) of Germany (1850-1939). There are also published data on heights of military recruits from the Imperial German military forces in 1906. These can be linked to areas in the database and related to breast feeding practices and infant mortality both contemporaneously and approximately 20 years previous to 1906. Results indicate a significant effect of infant feeding practices on later life outcomes operating through infant health conditions, proxied by the infant mortality rate.     

Some neuroanatomical aspects of primate locomotor evolution

Primate locomotor patterns are the result of osteological and myological interactions, the effectiveness of which is governed by various afferent, internuncial and efferent central nervous system pathways. The distribution of primary afferents following lumbosacral ganglionectomies and the distribution of corticospinal fibers following lesion of contralateral motor cortex to medial and lateral ventral horn motor nuclei have been discussed for the tree shrew and bushbaby. Based on limited data it has been suggested that the tree shrew is the best living example of the quadrupedal Paleocene forms from which primates presumably evolved, and the bushbaby is one of the best examples of the vertical clingers and leapers which appeared in the Eocene. Both forms have dense primary afferent distribution to cells of the lateral portion of the ventral horn, which are related to appendicular musculature, and sparse projection to the medial part of the ventral horn which innervates axial musculature. Corticospinal fibers in the tree shrew do not synapse in any portion of the ventral horn at any spinal cord level. The bushbaby has direct cortical motor control over cells located in the medial portion of the ventral horn and, consequently, over axial musculature. Extrapolations from studies on the tree shrew and other generalized forms suggested that Paleocene quadrupeds lacked cortical control over axial and appendicular musculature and depended primarily on subcorticospinal pathways and spinal reflexes for the execution of their locomotor pattern. Eocene vertical clingers and leapers retained the reflex pathways of their Paleocene ancestors but acquired direct cortical motor control over axial musculature, thus indicating a first level of neuroanatomical adaptation related to evolving locomotor styles. It was suggested that there are correlations between locomotor style and neuromorphological specializations, and that comparative observations on key extant phylogenetic forms may provide a clearer and more complete picture of initial locomotor adaptations in the primate series.