154 



^ KNOVV-LEDGE ♦ 



[Mat 1, 1888. 



batteries or small accumulators. The weight of several 

 patterns of these scarcely, if at all, exceeds the weight of some 

 patterns of oil lamps at present in use. They give a light 

 for at least twelve hours without any attention, exceeding 

 in intensity that of the ordinary oil lamp, and they can be 

 placed in rewy position, so as to illumine the roof, the floor, 

 or the sidfs of the mine, wherever the coal is being " got." 

 In fact it has been objected that they give too much light, 

 and that miners who use them are liable to be frightened 

 when they see the risks they run ! The incandescent fila- 

 ment is doubly protected, first by its own globe, secondly 

 by a very strong glass cap, and sometimes there is water 

 between them, as a precautionary measure. I entirely 

 demur, however, to Mr. Williams's statement that " the 

 breaking of the glass bulb of an incandescent lamp would 

 expose a filament of burning carbon nearly as dangerous as 

 a flame," and I venture to think that if Mr. Williams bad 

 tried to explode a mixture of fire-damp and air by breaking 

 such a lamp in it, he would have found it a much more 

 diflicult task than he imagines. As a matter of fact, the 

 filaments used in these small lamps are so minute, that even 

 if they escape being quenched by the water (supposing that 

 to be present) there are only very few explosive mixtures 

 which they can be made to fire. Mr. Williams's last 

 objection, that " their woi-st defect is the absence of warning 

 which is given by the behaviour of the common lamp 

 flame," was met more than a year ago by Mr. J. W. Swan 

 (formerly of Newcastle), with whose lamp I am tolerably 

 familiar. To this lamp a most ingenious firedamp indicator 

 is attached, which not only gives warning, but enables the 

 overman, or even the trained miner himself, to ascertain, by 

 an observation lasting only a few seconds, how much (within 

 0'5 per cent.) firedamp is present in the atmosphere at the 

 moment of observing. 



The question of comparative cost can, of course, only be 

 arrived at by the use of these lamps on as large a scale as oil 

 lamps are now used, in some large well-managed mine. As 

 some thousands of these lamps are coming into use, we may 

 shortly expect some reliable data on this point. I may 

 conclude by pointing out that, in the case of those lamps run 

 by poi table accumulators, the process corresponding to lamp 

 trimming is of the simplest possible description. In the 

 base of each lamp are two tiny sockets ; when the lamps are 

 handed in at the end of the shift's work, the sockets of each 

 one are fitted on to a pair of wires projecting from a board 

 on which hundreds of such lamps may be placed. These 

 wires are in connection with the terminals of a dynamo, and 

 thus, while the minere are above ground, one engineer 

 charges the whole of them, while his engine is probably 

 doing other work as well. Can anything be simpler ] 



DISEASE GERMS. 



lONE of the results of modern scientific 

 research are more interesting than the dis- 

 coveries relating to disease germs. Apart 

 from the relation of these discovei-ies to the 

 disetises which affect humanity, they are of 

 intei'est as disclosing to us a world of minute 

 life, of which in former ages men had 

 scarcely even any conception. They regai-ded plague and 

 pestilence as specially appointed visitations, not as obeying 

 laws as strict, though (even now) by no means so well 

 understood, as those regidating the development of the 

 higher forms of animal or of vegetable life. Possibly some 

 of those who are anxious to find constantly fresh proof of 

 the truth of the saying that there is nothing new under the 



sun, may consider that the modern theory of living death 

 germs is embodied in the sixth verse of the ninety-first Psalm, 

 where (following the Prayer-book version) we are told of the 

 " pestilence that walketh in darkness," and ihe " sickness 

 that destroyeth in the noon-day," but, on the whole, such 

 an interpretiition must be regarded as far-fetched ; and, 

 certainly, so far as definite statements are concerned, the 

 theory of poison germs must be regarded as less than a 

 century old. Within that time one disease after another 

 has come to be regarded as resulting from the development 

 of invisible germs by a process something akin to fermenta- 

 tion, sometimes more suggestive of algoid life. 



I do not propose to do more than touch here the general 

 theory of disease germs, considering more fully only the 

 evidence we have of the possibility, in certain cases, of 

 developing innocuous germs from those which produce 

 destructive diseases. 



At the outset I would touch on the curious question 

 whether a process akin to natural selection in the germ 

 world may not modify the character of these germs in ways 

 resembling those which have been adopted for their artificial 

 modification. The various forms of life represented by these 

 minute organisms have their stages of development like 

 the higher forms of life, but lasting a much shorter time, 

 so that within a very short portion of the life even of an 

 individual man, hundreds of generations of germ-life may 

 pass. Again, the lives of these germs doubtless depend on 

 their environment ; and the various species so undergo 

 during the course of many generations changes akin to 

 those which afl'ect (in many generations of their much 

 longer lives) the higher orders of life, animal and vegetable. 

 Hence, during the lifetime of an individual, and far more 

 during several generations (as we measure time) the character 

 of the disease germs to which small pox, typhus fever, 

 scarlet fever, measles, and other such zymotic diseases are 

 due, may undergo marked alteration. We could thus under- 

 stand the more or less deadly character of such diseases in 

 particular yeare, and also in particular regions. We can 

 also understand that some of the diseases of ancient times 

 which seem to have disappeared may in reality be repre- 

 sented by diseases of the present day which resemble them 

 in certain respects, but are nevertheless distinct diseases, 

 and in particular difler markedly in destructiveness. 



For example, the plague, as known in Europe only two 

 centuries ago, has certainly no modern representative in the 

 countries where it was once so greatly feared — if it exists 

 anywhere. What is to-day called " the plague " in Oriental 

 countries is a difterent disease. Yet there are reasons for 

 believing that our typhus fever is in reality akin to the 

 " black death " of old times. The story is well authenticated 

 which tells how in the place where certain victims of the 

 great plague of 1665 were buried, death and disease lurked 

 in wait, and nearly two centuries later found victims among 

 workmen employed to dig in the place where a pit had 

 been prepared for the corpses too numerous to be buried in 

 separate graves. But the illness which fell upon four of 

 these workmen, and on seventy others who contracted it 

 from them, was not the plague but simply typhus fever. 

 Assuming, as we may faii-ly do, that the germs of the plague 

 disease caused the fever which attacked these nineteenth 

 century workmen, we have evidence that the typhus fever 

 of our time is the direct descendant of the plague of former 

 ages. For, as Miss Florence Nightingale neatly put the 

 problem of the propagation of disease, small-pox can no 

 more generate scarlet fever, or scarlet fever measles, than a 

 race of dogs can produce a race of cats, or a race of cats a 

 race of rabbits. Typhus, generated by germs of the plague 

 disease, indicates clearly the kinship of the two diseases, 

 distinct though they now seem. 



