100 PROGRESS OF MICROSCOPICAL SCIENCE. 



as they get larger, into irregular sinuses, and are then seen to contain 

 masses of vegetation similar to those which have been already de- 

 scribed in the lymjihatic system of the corium — with this difference, 

 that the filaments of which the masses are composed are of such 

 extreme tenuity, and the conidia are so small and numerous, that the 

 whole possesses the characters of zooglaoa rather than of myceliima. 

 However, the author has no doubt that these aggregations are produced 

 in the same way as the others, viz. by the detachment of conidia from 

 the ends of filaments. In the earlier stages of the process the cavities 

 contain scarcely any young cells. Sooner or later, however, so much 

 of the rete Maljiighii as lies between the horny stratimi and the papillae 

 becomes infiltrated with migratory lymph-corpuscles. The process can 

 be plainly traced in the sections. At the period of vesiculation, i. e. at 

 a time corresponding to the commencement of the development of the 

 vesicles in the rete Malpighii, the cutis (particularly towards the 

 periphery of the pock) is infiltrated with these bodies. No sooner 

 has the coalescence of the vesicles made such progress as to give rise 

 to the formation of a system of intercommunicating sinuses, than it is 

 seen that the whole of the deep layers of the rete Malj)ighii become 

 inundated (so to speak) with migratory cells, which soon find their 

 way towards the cavities, and convert them into microscopical col- 

 lections of pus corpuscles, the formation of which is proved to be due 

 to migration from the corium, not only by the actual observation of 

 numerous amoeboid cells in transitu, but by the fact that the corium 

 itself, before so crowded with these bodies, becomes as the pustulation 

 advances entirely free from them. 



8. The concluding section of the paper is occupied with the 

 description of the secondary eruption, the anatomical characters of 

 which closely resemble those already detailed. 



On the Morhid Anatomy of Progressive Muscular Atrophy. — In a 

 very valuable pathological contribution,* Dr. Lockhart Clarke has 

 described the microscojiical appearances observed in a case of muscular 

 atroj)hy, accompanied by muscular rigidity and contraction of the 

 joints. The parts received for examination were a slice of one of the 

 cerebral hemispheres, the cerebellum, pons Varolii, medulla oblongata, 

 and spinal cord. The white substance of the brain was rather thickly 

 interspersed with corpora amylacea, from about twice the diameter of 

 a blood disk to fourteen times that size. In the grey substance only a 

 few of these bodies were present, and they were confined chiefly to the 

 deeper layers. These are thus detailed by Mr. W. B. Kesteven in the 

 ' Medical Eecord,' June 24th : — 



It is here worthy of note that in chronic disease of the brain and 

 spinal cord the presence of bodies, of varying size and far from uniform 

 aspect, to which the name of amyloid bodies is generally given, is by' 

 no means uncommon. At the same time there are forms of degenera- 

 tion of the neuroglia which give rise to appearances so closely re- 

 sembling the so-called corpora amylacea that it is an extremely difficult 

 thing to distinguish between them. Minute spots of miliary sclerosis, 



* ' Medico- ClururKical Transactions/ vol. Ivi. 1873. 



