MEDICAL MICROSCOPICAL SOCIETY. 315 



15th May, 1874. 



Molluscum Jihrosum (? Gheloid) . — Dr. Pritchard "mentioned the 

 case of a negro, who for twenty years had been subject to a growth 

 originating behind one ear, and gradually extending over nearly 

 all the body. After death a portion of the skin with growth was 

 forwarded to him (from America), as illustrating " Cbeloid simu- 

 lating Molluscum Jibrosum.'''' Microscopically, the cutis vera was 

 found hypertrophied ; here and there masses of cells between the 

 fibres of the areolar tisssue ; epidermis much thickened, hair- 

 follicles normal ; papillae had grown regularly and sideways, and 

 not vertically as normal. He considered it simply a case of Mol- 

 luscum Jibrosum, not of Cheloid. Engravings of the patient, with 

 specimens of the disease, were exhibited. 



Mr. Needham thought the condition of the papillae normal in 

 the negro. 



Perivascular Spaces in the Brain. — Mr. Kesteven read a paper 

 on this subject, illustrated by drawings and specimens. These 

 spaces had been considered normal structures, intended to relieve 

 intracranial blood-pressure ; but Mr. Kesteven had never seen 

 them in a really healthy brain ; had often noticed them associated 

 with chronic cerebral mischief, and hence concluded they were 

 owing to absorption of brain-substance by the irregular circulation 

 that goes on in chronic disease, the vessels being at one time full, 

 at another nearly empty. Though the mode of preparation in 

 chromic acid might render these spaces more evident by the 

 shrinking of the blood-vessel, he did not think it sufiicient to 

 account entirely for them. He could find in the perivascular 

 spaces no resemblance to normal lymphatic structure, while Dr. 

 Batty Tuke had now abandoned the idea that they denoted a 

 healthy condition of brain. Dr. Pritchard considered them entirely 

 owing to the mode of preparation in chromic acid ; he had never 

 found them in sections made by freezing the brain. Mr. Need- 

 ham argued their belonging to the lymphatic system, though not, 

 strictly speaking, " lymphatics." The President explained them in 

 some cases by the giving way of the capillaries around which they 

 were found ; he had seen the brain-substance stained with hae- 

 matin in their vicinity ; hence an explanation, perhaps, for some 

 of the anomalous convulsions of childhood. Thought proof was 

 wanting of their connection with the lymphatic system. Mr. 

 Toirard asked if in injected brains these spaces were seen, or 

 were obliterated by the distension of the vessel. In reply, Mr. 

 Golding Bird stated that he had never seen them in injected 

 specimens. Mr. Groves asked if Mr. Kesteven had ever examined 

 the spaces by staining with nitrate of silver? Mr. Kesteven, 

 quoting Mr. Batty Tuke, stated that the spaces had been found 

 in the lower animals (e.g. cats) after strangulation; and that, 

 though the vessels thus remained full, a space could be seen 

 beyond. He had never seen anything to warrant the supposition 

 that they were owing to haemorrhage. He knew of no anatomist 



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