CHAPTER IV.

The measles contagium-Hallier's work-De Bary's contemptuous opinion of it and his views on the relation of bacteria to fungi-Too sweeping and premature (?)—“The straw fungi ”—Puccinia graminis—Question as to its strictly obligate parasitism in vegetal hosts-Its effects on farm labourers-Its facultative saprophytism (?)-Excreta of vegetable feeders-Suggestion that they carry on the Puccinia-Facts not taken into consideration-Is the Puccinia represented in the straw used in bedding?

THE precise nature of the measles contagium is, of course, at present matter of pure speculation. Since Hallier's cultivations, several inquirers, singly and in pairs, have examined the fluids and tissues of measles patients; and when each of these researches brought out what was taken to be the specific pathophyte, there was an end of it.

Whether Hallier ever really succeeded in converting any of the pathophytes into fungi, or was deceived in his results in every instance, would seem to be doubtful, notwithstanding that botanists have declaimed against the imperfections in his method and impugned the trustworthiness of his observations. It is not impossible but they have been too sweeping in their condemnation, and that they may be found hereafter to have overshot the mark. Be this as it may, looking at Hallier's cultivations of the measles contagium it is certainly very singular, to say the least, that he should have brought out Aspergillus, Ustilago, Eurotium, and Mucor, each of which is to be found at times on straw. Taking the results into consideration with the extrinsic evidence that the "straw fungi" are concerned in the causation of measles, they look very like

the outcome of genuine work. That these forms were associated with measles so intimately, that it was not until after repeated cultivations that Hallier concluded that the Mucor is the specific cause of the disease, was an uncommon result in micropathological research; but it squares perfectly with the variations in the results of those investigators who have examined the measles contagium. That Aspergillus and Ustilago should have been so well represented in the contagium as to have come out, as well as Mucor, in Hallier's culture processes, is in accord with Dr. Salisbury's inoculations and with well observed conditions preceding the occurrence of measles.

Vogel, according to Thomas (Ziemssen), "contests most decidedly the possibility of proving" Hallier's statements in regard to his cultures. But whatever objections may be taken to them on the ground of the impossibility of showing the continuity of the forms in the blood with the fungi that appeared in Hallier's laboratory, there are some strong reasons for concluding that whether the fungi came, or did not come, legitimately, of the forms in the blood of the measles patients, identical or closely allied species of fungi had their representative forms in that blood. Even if Hallier did not get the fungi he names out of the measles contagium, it is an inference that like or kindred fungi were there, potentially, in the contagium. The whole subject of the relations of the bacteria to other fungi, however, is in effect in a state of suspense pending further discoveries. Botanists are as yet stiffly opposed to the view that the bacteria are in any way connected with ordinary fungi. De Bary, one of the most pronounced opponents of morphosis in this kind, says in his last great work:-"Bail, Hoffman, and especially Hallier, were the chief representatives of these pleomorphistic extravagances. Others eager to share the laurels of these discoverers modestly adopted their views. So far as these observations possess any historic interest in special cases they will be mentioned in succeeding sections. Such of them as, like Hallier's especially, only belong to the scientific chronique 1 Comparative Morphology and Biology of the Fungi Mycetozoa and Bacteria, p. 127.

scandaleuse will not be further noticed." In the same work at p. 474 occurs :-"As regards the place of the Schizomycetes in the natural system, it is apparent from the foregoing statements that the course of their development does not point to any close affinity with the fungi. To say that they are offshoots of the fungi is to 'contradict all trustworthy observations' so flatly, that the view need not be seriously discussed in this place."

Undoubtedly De Bary was in the very foremost rank of botanists; and he has left his mark behind him in some superb work. When such a man pronounces with such decision on a question within his own province, it might be deemed presumptuous to suggest, but that he almost invites the suggestion, that he may have overlooked certain facts, or that he may not have had his attention drawn to certain phenomena that might, had they been present to his mind, have affected his conclusions. Indeed the absolute certainty with which De Bary speaks now and then is curious to see side by side with admissions that he was formerly wrong in this or that matter-admissions made as frankly and unhesitatingly as though it were the most natural thing in the world to be wrong. No one could better afford

to admit an error here and there in his observations and inferences, but the peremptory way in which he dismisses the question of close affinity between the Schizomycetes and the Fungi would seem, in the present state of knowledge, to be somewhat premature even on his own showing. In his "Lectures on Bacteria" (p. 73) he says:- -"We are still very much in the position of beginners as regards our knowledge of these matters. ... We must keep clearly in mind that our knowledge of the morphology and biology of the Bacteria is at present very imperfect, or at least very imperfectly developed. So much is this the case that we are not yet in a position to attempt a consistent classification and nomenclature on the principles of systematic botany. What at present seems like such a classification is only a temporary expedient. In such a case the only thing to be done is to agree upon a provisional arrangement and nomenclature for the time being." It is hard to reconcile these candid expressions of nescience in regard to the morpho

logy and biology of the Bacteria with the unqualified rejection of the view of organic continuity between them and the other Fungi-the more especially that finality has not been reached with respect to our knowledge of the morphology and biology of the latter. Indeed [confining the purview here to the Schizomycetes concerned in infective processes in animal organisms], if we look at such exanthematous affections as have been frequently observed to follow the imbibition of fungi [notably, for instance, the peculiar eruptive fever caused by handling the larger reed, Arundo donax, when it has been cut and exposed for some time to the weather], and even if we exclude from consideration the results of the inoculation of the straw fungi, it would seem to be hazardous to lay down the hard and fast dogma that there is no close affinity between any of the Schizomycetes and the Fungi.

It is not necessary to the present purpose, and it is beyond the scope of this work, to make the attempt to show the connection that, as I conceive, exists between some of the bacteria and the fungi. Nor do I feel called upon to suggest a mode by which the morphological change of form from the fungus to the disease-inducing bacterium may be brought about. It will be sufficient to produce facts which have been overlooked by botanists and others, tending to show, either that certain schizophytes are direct descendants of certain parent-fungi or that certain fungi are invariably accompanied by certain schizophytes. Although of large importance biologically, it does not much matter etiologically, and it obviously makes no difference to the hygienist, whether a given pathophyte is the actual scion or the inseparable companion of a given fungus; but the conclusion that one or other of these relations obtains between some of the bacteria and the fungi would appear, from certain phenomena, to be almost forced. I incline strongly to the view that the bacteria in question derive immediately from the fungi with which they are associated; although the biological knowledge of the present day furnishes no explanation of the morphoses, and no proof of the continuities. This, however, is no insuperable bar to the supposition of intimate relation

ship; for, judging by what has transpired of late years in this domain of botany, we may soon have further discoveries to enlighten us as to the stages of the cycles.

The immense difficulties standing in the way of research in this field owing principally to the extreme minuteness of the forms to be investigated, may have intervened hitherto to prevent observers from witnessing the morphological processes by which fungi are converted into bacteria, and may serve to account for the apparent break in the continuity of the forms which has led to their disconnection in the botanical system: but whether botanists shall eventually be proved to be right or wrong in drawing the line of demarcation between them, it is clear that up to the present time they have had no further warrant for doing so than the fact that, so far, nothing has been seen or advanced to justify the view of consanguinity, together with the fact that the view is not in accord with the received laws of biology. That is to say, botanists have rejected the supposition partly on negative evidence and partly on the ground that it is difficult to conceive how, on present biological principles, the morphological changes occur.

If this latter objection had been founded on full knowledge of the life of these organisms, it would unquestionably have been valid; but botanists admit that as yet they are but on the threshold of inquiry into this vast subject. Therefore the question whether the disease-causing Schizomycetes do or do not derive from the fungi resolves itself into one of judgment: and though the weight of authority is mostly on the one side, it is there on the strength of views which, avowedly, may be upset by further biological research. And as botany has in modern times seen radical changes and complete upheavals of views that were supposed to have been fixed for ever on the solid basis of fact, it will not be so surprising if future discovery end in reversing a view which has been arrived at on insufficient or unfinished observation. Consequently until it has been shown, scientifically, that a given bacterium is, or is not, a good species, the true place of the Schizomycetes in the system may be regarded as uncertain, notwithstanding the dicta of the