Notes and Memoranda

ABSTRACT Dr. Klein’s supposed Mycelial Growth in Sheep-pox.—The remarkable appearances detected by Dr. Klein in the tissues of sheep suffering from variola ovina, which were considered by many eminent naturalists after inspection of his preparations to be parasitic organisms similar to the mycelium of a fungus, have been proved to be artificially produced coagula of albuminous matter. Dr. Klein’s report to the medical officer of the Privy Council and his drawings were reprinted in this Journal last year. At the last meeting of the Royal Society, in June, a paper was read by Dr. Creighton, lately engaged in the Brown Institute, in researches on the pathology of cancer, in which that gentleman showed that appearances similar to those obtained by Dr. Klein were obtained abundantly in preparations of healthy tissue treated when perfectly fresh with hardening reagents. Dr. Creighton’s preparations consisted chiefly of sections of the mammary gland. In a note read at the same time Dr. Klein accepted the explanation of the mycelium-like appearances given by Dr. Creighton. Though the supposed proof of the parasitic nature of variola has thus been swept away, it must not be supposed that there was not large justification for regarding the coagula as specific organisms. The filamentous branched and knotted appearance which they presented was strangely like that of an organic growth. Their minuter structure, whilst differing from that of an ordinary fungus-mycelium in showing no differentiation of a cell-wall, agreed with such in the presence of vacuole-like spaces and in the excessively fine granular character of the supposed protoplasmic substance. In many cases the branching filaments met together and formed a network, which is unlike any growth exhibited by an ordinary fungusmycelium, but suggestive of a naked protoplasmic mycelium, similar to that of the Myxomycetes. Whilst we have, then, lost, or rather not gained, an advance in our knowledge of the contagium of variola, we have gained a very important lesson in the necessity for being on our guard as to such artificial results due to our methods of manipulation as are these mycelioid coagula. Already in another branch of histological inquiry observers have been on their guard against the deceptive appearances of membranes and fibres produced by the coagulation of albuminous fluids when acted upon by the hardening reagents used in the laboratory. One of the most careful and accomplished of the younger German histologists, Dr. Flemming, of Kiel, makes the following remarks in a memoir on the “Anatomy and Physiology of Connective Tissue “. (‘Archiv für Mikrosk. Anatomie,’ 1876, vol. xii, p. 396):—” I have worked for some time with this combination (osmic acid and anilin), and have found, as is well known, no doubt, to others, that one must not accept as veritable structure all that it brings into view. Notoriously, osmic acid, like other hardening reagents, produces coagulation of the albuminous fluids of the body, such as blood, serum, and lymph, and the coagula become deeply tinted with the anilin dye. In fact this kind of coagulum can be obtained without previous application of osmic acid by the action of the simple solutions of the anilin pigments, most abundantly, as one might expect, by the use of alcoholic solutions, but also by the use of aqueous solutions. I would never undertake to say that membranous-looking things, such as this treatment has yielded me, with loose connective tissue, are really membranous and not coagula.” Professor Flemming observes that one can most satisfactorily convince oneself of the occurrence of these albuminous coagula in blood- and lymph-vessels by the study of animals which have not been killed by bleeding (a case which applies very well to the excised portions of tissue studied by Dr. Klein), and, perhaps, best of all by the study of embryos; the parietal cavities and the vessels of the latter are almost always, after treatment with osmic acid, filled with coagulated masses which take up the staining.