PBOGRESS OP MICROSCOPICAL SCIENCE. 271 



This was shown by a filtration experiment, where the organisms were 

 retained upon the filter (fine thick non-sized printing paper ; Swedish 

 filtering paper does not do) which remained luminous, while the 

 lierfectly clear filtrate was absolutely non-luminous, this clearly 

 showing that the small living cells of the schizomycetes are the cause 

 of the luminosity ; and further, the author's experiments furnish 

 strong proofs that the schizomycetes do not arise " spontaneously," but 

 from spores. 



On the Development of Spindle - cells in Nested Sarcomas. — 

 Dr. Gowers read an able and interesting paper on this subject before 

 the Pathological Society, which has been thus reported by the 

 ' Lancet ' of April 22 : — The tumours thus designated consisted of 

 spindle-cells with a few round cells, and had, further, this pecu- 

 liarity, viz. that the spindle-cells were in part arranged concentrically 

 in nests, resembling very closely the nests of epithelioma. The 

 microscopical characters of the cellular elements were fully detailed. 

 The nuclei of the cells were larger in proportion to the size of the 

 cell in the softer and more rapidly growing parts of the tumour, 

 while in the denser portions the cells were finer and more like fibres. 

 In some parts, round cells were observed in process of development 

 into the spindle-shaped varieties. The " cell-nests " varied from ^-^ 

 of an inch to o J-jy of an inch in diameter, and were distinctly seen to 

 be composed of concentric layers of fusiform cells, the outermost 

 layers being in many specimens partly detached. These observations 

 were founded upon three examples of the tumour which sprang from 

 the inner surface of the cranial dura mater : they were globular and 

 nodulated, and had displaced the brain-substance in their vicinity. 

 They varied in consistency, but the older portions of the growths 

 were firmer than the more recent parts, and in one specimen the 

 whole tl^mour was soft throughout. In colour the growths were of 

 a reddish grey, the softer parts resembling in tint and consistency 

 grey cerebral substance. In these tumours the origin of their con- 

 stituent spindle-cells could be readily traced ; the process being 

 foimd to consist in an endogenous development from round cells, 

 the process described as vacuolation by Dr. Creighton. The fol- 

 lowing is a brief outline of the changes as observed in different 

 stages of progress in different parts of the growth. The nucleus 

 of the small delicate-walled round or oval cell, which is at first in 

 or near the middle of the cell, becomes excentric in situation, whilst 

 a clear space occurs in that part of the cell which is away from 

 the nucleus ; and as the cell increases in size its granular proto- 

 plasmic contents become more and more confined to the periphery, 

 till at length the " crescentic " or " signet-ring " form of cell is 

 produced. The nucleus now lies imbedded in the protoplasm where 

 this is thickest. Gradually the inner margin of the crescent-shaped 

 body becomes more defined, until at length there is produced a 

 spindle-cell, which gradually separates from the central mass of the 

 original cell-body. Many were seen in process of separation, and in 

 those recently detached their crescentic shape denoted the manner in 

 which they had arisen. When the original nucleus remains single 



