The cortex of the brain in the human embryo during the fourth month with special reference to the so-called 'papillae of Retzius' / by George L. Streeter.

  • Streeter, George Linius, 1873-1948.
Date:
[1907]
Catalogue details

Licence: In copyright

Credit: The cortex of the brain in the human embryo during the fourth month with special reference to the so-called 'papillae of Retzius' / by George L. Streeter. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    smoothed out later by the development of the adjacent layers. Shortly after this Hochstetter, 98, p. 5, briefly refers to the granulations of the pyramidal cell layer described by Retzius. He confirms their presence in poorly preserved brains, and designates this appearance as a decomposition phenomenon, without giving any further evidence. Two years later His, 00, not having noticed the observations of Retzius, described independently the same peculiar granular or wart-like character of the pyramidal layer in embryo brains of the fourth month; and again in his last work His, 04, he describes at some length this appearance under the title “ Die Retziusschen Warzchen.” One of his illustrations is reproduced in Fig. 1. Though in his discussion he admits that it is Fig. 1. Pio. 2. Fig. 1. Section through the occipital lobe of the brain of a human embryo, 12 cm. long (end of 4th month), showing the irregularities of the pyramidal zone caused by the fungiform clumping of the cortical cells, the so-called papillae of Retzius. Taken from His, 04, Fig. 75. Fig. 2. Section from the brain of a human embryo of about the same age and taken from the same place as shown in Fig. 1. Here the pyramidal zone consists of a compact layer with parallel borders, which, with the excep- tion of three transitory fissures presents a perfectly smooth outer surface, and shows no trace of the Retzius papillae. still an open question; yet he is apparently inclined to consider the papillae as normal, and does not hesitate to discard the possibility referred to by Retzius of their being pathological, on the ground that several of his specimens, which showed characteristic cortical papillae, came from healthy individuals who had committed suicide, and the foetuses them- selves appeared normal. He also argues that if it were a post-mortem alteration, associated with the swelling of the tissues, then the superficial la}rer would also present an irregular surface, which is not the case. Neither His nor Retzius accounted for the fact that this phenomenon