SEVENTH WINTER MEETING—FEBRUARY 7th, 1905. 



"BACTERIA."— By Dr. IITTOCK, J.T., F.R.M.S. 



The spventh winter meeting took place on 

 February 7th, when Dr. Pittook gave a lecture of 

 great interest, entitled " Micmbes and Disease 

 Germs." After a few preliminary remarks, the 

 lecturer said : The study of bacteriology is asso- 

 ciated with Boaie most important branch^-a of 

 enquiry. For instance, the origin of life — is there 

 sucb a thing as spontaneous generation, as it is 

 called r Do living things, or the earliest forms of 

 life, originate sp 'ntaneuusly, as it were, from dust 

 and dirt, and from putref > ing substances ?^a 

 controversy which hns occupied the minda of 

 philosophers and naturalists forages. Again, what 

 can exceed the impnrtance of another branch of 

 bacteriological enquiry which is concerned with 

 the microbic origin o^ disease, and th« toxins or 

 poisons produced by them in living bodies? Lord 

 Lister, in his presidential address on the anni^^er- 

 eary of the Royal Society, paid "There is no subject 

 in biolosry (f greater inteiest at the present time, 

 whether from a scientific or a practical point of 

 view, than that of tne Serum treatmeut of 

 infectious diseases." These and other questions 

 then will come within the scope of my lecture. I 

 will begin by a general description and account of 

 the various kinrts of microbes, and afterwards will 

 attempt a mure minute survey of the special forms, 

 their appearance and characteristics, and the 

 effects produced by them. Microbes, or germs, are 

 every where, in the air we breathe, the food we eat, 

 the water we drink, the ground we tread on ; they 

 swarm in all decaying substances, and even our 

 bodies are the homes and the happy hunting 

 grounds of countless myriads of them. Dust and 

 dirt, h >wever, are the general carriers, feeders, and 

 breeding grounds of them. The moats in the sun- 

 beam, as seen crossing a dark room, consist largely 

 of these tiny spirits. Their exceeding minuteness 

 almost boffles comprehension. A commtm size is 

 about one twenty-thousandth of an inch ; that is 

 to sav, that 4tK) millions of them could fiud ample 

 standing room on a postage btamp. This number 

 would be about a buodred times the population of 

 modern London And yet. small as they are, their 

 shape and structure can easily be shown by the 

 highest powers of our modern microscopes, which 

 have reache<1 such a pitcti of excellence as to be 

 al'le to maijnify an object from one to three 

 thousand diameters. That is to say, a microbe of 

 one twenty-thousandth of an inch liiaineter can be 

 made to appear one twentieth of an iuch in size. 

 When thus magnified, some ot these little 

 bodies are seen to be simple roand granules, 

 Chlled cocci ; Some called bacilli, are rod shaped ; 

 and some are spiral or cork-screw shaped, and are 

 di tinguished as spirilla But the convenient 

 collective name for them all is 6acie'-ia, or they 

 may all be spofeen of as microbes or germs. The 

 yeMSt germs, as we shall presently see, are some- 

 what Ian;er and are oval io shape, and often 

 united into branched thread-like bodies. The 



bacteria mostly, especially the spiral forms, have- 

 the power of free movement in air and liquids. 

 Some spin like a top, some travel in a tortuuus or 

 serpent-like manner, and many of them can dart 

 rapidly acrt>s5 the field of observation, producing, . 

 when in countless numbers, a very curious and 

 entertaining sight. Microbes increase and ojuUiply 

 with astonishing rapidity, mostly by t-ub-division 

 or splitting in pairs. A single bacillus may thus 

 become two in an hour, four in a second hour^ 

 eitjht in the third. A very simple calculation 

 shows that in this w<iy one microbe* may produce 

 sixteen million individuals in twenty-four hours. 

 But, for their favourable development, they require 

 a certain temperature, moisture, and favouiable 

 food or nourii-hment. There are num* n us ag* nciea 

 at work to keep their numbers within reasonable 

 limits, so that the atmospheres and waters m^y 

 not be oveicrowded with them. Many of them 

 prey upon each other, still moie beC"me the prey 

 of otber living things. Many again are kill d by 

 the products of their own secr^-tion. The jeast 

 germ, which converts sugar ii.to ale hoi, is killed 

 when the spirit exceeds a certain strength (a warn- 

 ing to all who paitake of strong waters), and the 

 microbe which converts alcohol into vinegar, 

 though capable of cons-uming an »m'-urit ot s-piiit 

 which would put the most confifm^d druukard to 

 shame, refuses to take its grog any stionger than 

 one-tenth alcohol, and cannitt live 'n strong spirit. 

 This seems to be an appropriate pUce to speak ot 

 an extraordinary provision of Nature by which 

 the animal body in heali h i? guarded from the 

 attacks of noxious kinds cf bacteria. The white 

 corpuscles of the blood of animals have the power 

 of absorbing and destioying these germs, litis 

 singular faculty of the white blo^H c^Hs was first 

 pointed out by the celt-btated Rui-pian physiologist, 

 Metschnik- ff, by whom these pr.t- ctive cells were 

 named phagocytes, or germ swaltowers In heal'h 

 the wartaie between thepe good truaidian cells and 

 the intruding geims is con>tan'ly tf-ing on, and it 

 is prubably only in disordered anH eufeebli-d con- 

 ditions of the body that this power of defence 

 fails. There is another way in which 

 microbes multiply, and that is by spores, 

 which are round or oval bodies, foi m -d 

 in the interior of a bacillus, and set free on the 

 death of the microbe. These spo-e r- far hardier 

 than the parent germ, for wherens nil badl i may 

 be killed by treezmg or boiling, these Fpi-res can 

 resist extremes of cold far beyond the tie^zint;- 

 point,and will even survive continued hi'iling la 

 tact, they are among the most inde^truc'ihle forms 

 of living matter yet known. M'lreov^r. they mny 

 remain unaltered for years, and y^'t, under tavouc- 

 able conditions, will revive, giow rapidly, and 

 speedily become bacteria like the pHrent. Ttiia 

 power of revival and tjrowth whs taken advarttage 

 of by Pasteur, Tynd>ill, and others in their experi- 

 ments to sterilize tluide, as it is called, that ia ta 



