524 SUMMARY OF CURRENT RESEARCHES RELATING TO 



b. Histology. 



Nuclear Substance and the Origin of Fibres.* — Gaylor Swindle 

 has previously sought to show that neurofibrils and neuroglia-fibres are 

 due to elongated nuclei or elongated chromatin particles. He has 

 extended this idea to other tissues, e.g. to the connective-tissue fibres 

 of the urinary bladder. The fibres of the mesentery, of the cutis, of 

 epithelial cells, and so on, are all due to nuclear metamorphosis. The 

 same is true of the tail of the spermatozoon. 



Nissl's Granules.! — M. Muhlmann defends the conclusion which 

 he previously argued for, that Nissl's granules, which occupy the spaces 

 between the neurofibrils in the nerve-cell, have a nuclein content along 

 with a globulin body. This is supported by Herwerden's experiment 

 on the influence of nuclease on the nerve-cell. It appears from Miihl- 

 mann's observations, especially on the action of w T eak soda-solution, 

 that the nuclein of Nissl's granules is different from the nuclein of 

 nuclei. The tigroid nuclein of Nissl's granules is soluble in soda ; the 

 nucleus nuclein is not. The author criticizes ITnna's conclusion that 

 Nissl's granules consist of albumose. 



Structure of Vagus Nerve in Man.J — S. Walter Axon has dis- 

 covered a pyridin-silver technique, which gives a stain of the axons as 

 sharply differentiated as is the osmic acid stain of the myelin sheaths. 

 This shows that axons devoid of myelin sheaths are present in great 

 numbers in many parts of the cerebrospinal nervous system where it had 

 been supposed that only medullated fibres were to be found. A cross 

 section through the cervical trunk of the human vagus some distance 

 below the nodose ganglion shows that non-medullated fibres are present 

 in enormous numbers. Medullated axons are stained yellow, and are 

 surrounded by a colourless ring of myelin. Non-medullated fibres 

 are stained black and are sharply differentiated from the light yellow 

 endoneurium. Most of the medullated fibres in the thoracic vagus 

 leave it through the bronchial and oesophageal branches, so that the 

 vagus as it passes through the diaphragm is composed almost entirely of 

 non-medullated fibres and only a few scattered medullated fibres. Few 

 if any of the non-medullated fibres of the vagus are derived from the 

 sympathetic. They belong properly to the vagus and are present in its 

 roots. 



Minute Structure of Nerve-cord of AmphioxusJ — W. Stendell 

 describes the various forms of cell found in the central grey matter of 

 the spinal cord of the lancelet. "Edinger's cells" are well marked, 

 and their resemblance to the sensory spinal cells of the lamprey is 

 emphasized. According to Tretjakoff, these cells of the lamprey repre- 



* Anat. Anzeig., xlvi. (1914) pp. 560-5 (4 figs.). 



t Arch. Mikr. Anat., lxxxv. (1914) lte Abt., pp 361-3. 



t Anat. Anzeig., xlvi. (1914) pp. 522-5 (1 fig). 



§ Anat. Anzeig., xlvi. (1914) pp. 258-67 (7 figs.). 



