360 



♦ KNO^A^LEDGE 



[October 1, 1886. 



destroying most organisms ; it may be heated in the flame 

 of a spirit lamp, capable of burning any animal or vegetable 

 substance. It is then presumed to be ready, but the air of 

 the room may deposit some germ upon it ; the human 

 breath may do it ; it could not be touched on its surface 

 with the cleanest finger without detriment to its complete 

 purity; no instrument such as a glass rod can be safely 

 used to convey the bacterium it is desired to observe and 

 nothing else, unless it has been in the flame of a spirit lamp 

 immediately before its use. Experimenters, like Pa.steur, 

 investigating the air of mountain heights, take up with 

 them sterilised fluids fit for the growth of bacteria, &.C., in 

 glass bottles, hermetically sealed, and drawn out with 

 narrow necks. They break these necks to let in the air, 

 and then seal them up again with a spirit lamp. But the 

 nippers with which they break the necks may have germs 

 adhering to them, and they must not be used till they 

 have been passed through the hot spirit flame. 



In a case of Dr. Sternberg's his object was to ascertain 

 whether a rabbit was killed Isy micrococci (round forms of 

 bacteria) or by the poisonous action of the fluid in which 

 they were swarming. He accordingly introduced less than 

 one minim of the fluid with the micrococci in it, with sixty 

 times its quantity of a nutritive fluid, which he had sterilised 

 by heat. He thus grew a fresh crop of the little ferments. 

 Repeating this process eight times, the quantity of the 

 original fluid was lessened each time, until at last it only 

 formed one part in 1,679,611,000,000,000, -'yet a few 

 minims of this eighth culture possesses all the virulence of 

 the first." The virulence thus belonged to the micrococci, 

 and not to the original fluid. 



In one case of supposed discovery of a ferment of disease 

 the error arose from the glass slide containing in very 

 minute cavities exti-emely fine particles of rouge used in 

 polishing it, and which were taken for bacteria. 



The artificial culture of micro-ferments may be made in 

 infusions of animal or vegetable matter sterilised by heat, 

 or in chemical fluid.s, such as 



Distilled water, 2 c.c. 



Phosphate of potash, O'l gramme 



Sulphite of magnesia, 01 „ 



Tribasic phosphate of lime, 01 „ 



The general student who wishes to understand the nature 

 of micro-ferments, and to appreciate the labours of specialists, 

 can do so without much trouble or inconvenience. An 

 infusion of hay will supply several forms ; yeast is easily 

 obtained, and, where there is no handy place to keep oflfensive 

 putrefying infusions, enough may be done by opei'ating on 

 small quantities, although, as the researches of Dr. Dallinger 

 show, keeping considerable quantities for a long time is 

 the only way of obtaining some forms. As new readers 

 are continually studying the pages of Knowledge, we 

 reintroduce for their benefit some figures which appeared 

 in the number for June 1, 18S3. Nos. 1 and '2 repre- 

 sent the bacterium of tubercular disease multiiilied re- 

 spectively about five hundred and one thousand times; 

 3 is a common form in the scum of infusions ; 4, a 

 spii'illum considerably magnified ; 6 and 9 are other 

 forms ; 5, a long bacterian form ; 7 and 8, spores and 

 micrococci. Sometimes various little organisms occur 

 in masses of gelatinous matter, which have been called 

 " zooglcea." This happens with many species. The little 

 round forms can only be distinguished from one another by 

 watching their development, which often takes a shape 

 widely diflfering from the original germ. Dr. Dallinger 

 has traced the existence of whips as motive organs in 

 spirillum and other forms. In many cases this is quite 

 beyond the powers of ordinary students, as it can only 



be done with very costly objectives and the exercise of 

 long practised and great manipulative skill. In operating 

 with ordinary powers and upon common species, the 

 student must avoid excess of light. It is well to point 

 the microscope so as to receive light direct from a lamp 

 turned edgewise, and through a very small hole of a 



/// 



y^ 



»000O2OOOOOOO00CX3C00C> 



O o .A 

 Oo ;| 



' 8 



diaphragm or condenser, say, one-thirtieth of an inch 

 in diameter. 



To counteract the malefic effect of disease-producing fer- 

 ments there are two courses : one, to kill them by some 

 substance that poisons or otherwise destroj's them, tlie other 

 by rendering the fluid in which they live unfit for their 

 propagation. Acetic acid is reported as having little effect 

 as a germicide. Alcohol also has small value ns a germicide. 

 Camphorated alcohol is said by Dr. Sternberg * to be trusted 

 by French surgeons to purify their instruments, althougli 

 while it kills some mischievous organisms it does not affect 

 others, such as the bacteiium of anthrax (wool-sorters' 

 disease). Arsenioiis acid is not fatal to all forms. Carbolic 

 acid, in the proportion of 1 to I'OO, destroys B. tenno and 

 the septic micrococcus in active growth, while 1 : '25 failed 

 to destroy bacteria in broken-down beef-tea. Eucalyptol, 

 the active matter in the blue gum of Australia [Eucab/ptus 

 globulus), retards, and in some cases stops, the de- 

 velopment of bacteria. Ferric sulphate is mostly use- 

 less as a germicide, but good as an antiseptic. 

 The same may be said of boracic acid, which, 

 as proposed by Barff, is an excellent preservative of all 

 kinds of food. The heat death-point of these ferments 

 varies greatly; 140° F. will destroy many, but some resist 

 a temperature considerably above the boiling-point of water. 

 Sjjores of B. subtilis in hay infusion are said to withstand 

 boiling for five hours. 



A veiy curious question arises concerning the protective 

 action of inoculation and vaccination. Do they make some 

 permanent change in the vital fluids, or how do they act ? 

 Dr. Steinberg says that if the first theory is true, the flesh 

 of a protected animal made into broth ought not to suit the 

 growth of the organism used in the protective inoculation ; 

 but this is not sound reasoning, inasmuch as dead l^roth is 

 not the same thing as the fluids in a live and healthy 

 organism. No conclusive explanation has yet been given. 



Poker Pickings. — The judge, the .sheriff, the coroner, and the 

 chief of police of Red Gulch, were engaged in playing poker. The 

 pot was pretty large, and considerable excitement was manifested 

 in the outcome. The judge "called" the sheriff, who casually 

 remarked—" I hold four aces. What do you hold ? " "I hold a 

 bowie knife," promptly returned the jud^e, as he perceived a tifth 

 ace in his own hand. " And I hold a six-shooter 1 " exclaimed the 

 chief of police, as he realised that he was not destitute of aces him- 

 self. . . . After an interval of about five minutes the coroner 

 crawled out from under the table, saying — " I hold an inquest, and 

 I guess that takes the pot." 



* " Bacteria," by Sternberg. 



