Bacillus

“ Experiments fully bore out this supposition, as no great difficulty was encountered in naturalising the Bulgarian bacillus in the large intestine, not only in milk cultures, but grown in solution of malt, bouillon, etc. It thrives in all kinds of sugar, and therefore can be administered in a variety of media, very beneficial results following in many cases. Direct tests showed a large reduction of the injurious intestinal 155 flora when the Bulgarian bacillus had been naturalised in the colon, and the bacillus persisted long after it had ceased to be administered. ”

“ The bacillus grows only in the absence of oxygen (strict anaërobe) , stains by Gram's method, forms terminal spores, and develops best at 22°C. Unlike most bacteria dangerous to man, it appears unable to grow in the human body, and its injurious effect is limited to the action of the toxin produced in foodstuffs outside the body. ”

“ The serum of an animal injected with one strain will agglutinate bacilli of another in high dilutions. Even the serological tests of patients suffering from dysentery caused by one type of bacillus give uncertain results. Penfold and others have shown that cultural reactions which are constant for one type of bacillus can be made to vary by growing the same bacillus under different conditions, and even passage through the intestinal tract of a fly may exert a temporary influence on their power of fermentation (Bahr) . ”

“ No growth occurs on potato, milk is not coagulated, and gelatine is not liquefied; Gram's method does not stain the bacillus, and there are no spores; the bacillus is readily killed by heat and by desiccation over sulphuric acid at 30° C. Both in cultures and outside the body the bacillus loses virulence. To this may be attributed possibly the variety of forms of the plague bacillus which differ in virulence. On gaining entrance to the human body308 the bacillus affects in particular two organs, the spleen and the lymph glands. ”

“ These predisposing factors render the tissues a fruitful soil in which the bacillus and its allies may germinate and thrive. I should like to touch briefly upon certain of these predispositions.
It was formerly held that consumption is a hereditary disease. But we know now it is practically impossible for such to be the case, for parents can not transmit the bacillus to their offspring. What parents may transmit is a tendency to the disease, resulting from unhealthful conditions in their own organisms. ”

“ From the under-surface of the oil, if the bacillus be that of plague, stalactite-like growths of bacilli will form. When disturbed, the stalactite growths break off and fall in snow-like flakes to the bottom of the vessel. No other known bacillus behaves in this way. (See p. 325.) In case of doubt, animal inoculation should be had recourse to: a little of the virus from the patient or a culture is rubbed into a shaven area (1 in. square) on the abdomen of a white rat or a guineapig. ”

“ Other bacteria than the acid-fast group are stained blue by Gabbet's method. Those most commonly found are staphylococci, streptococci, and pneumococci. Their presence in company with the tubercle bacillus constitutes mixed infection, which is much more serious than single infection by the tubercle bacillus. It is to be remembered, however, that a few of these bacteria may reach the sputum from the upper air-passages. Clinically, mixed infection is evidenced by fever. ”

“ The brilliant idea occurred to Professor Metchnikoff, of administering acid-producing germs which might work their way 154 through the digestive system, and, reaching the large intestine, produce the acid required. After much experimenting the bacillus of Massol, Bacillus bulgaricus, was adopted as the most suitable. The Bulgarian bacillus is an extremely vigorous one, multiplying with great rapidity, and persisting in conditions that would be inimical to other microbes. The growth and development of bacteria is interfered with by the products of their own activity ”

“ That the bacillus of consumption should have been very frequently found in dust by different investigators is hardly surprising when it is realised that the sputum of phthisical persons may contain the tubercle germ in large numbers, and that until recently no efforts have been made in this country to suppress that highly objectionable and most reprehensible practice of indiscriminate expectoration. ”

“ All these modes of extension are well shown in tuberculosis. This disease is caused by a small bacillus which does not produce spores, has no power of saphrophytic growth under natural conditions, and is easily destroyed. Moisture and darkness are favorable conditions for its existence, sunlight and dryness the reverse. There are three varieties or strains of the tubercle bacilli which infect respectively man, cattle and birds, and each class of animals shows considerable resistance to the varieties of the bacillus which are most infectious for the others. ”

“ It has been stated that some enzymes are thrown out from the cell and others are retained within the cell. The same is true of toxins, hence we speak of exo-toxins or toxins excreted from, and endo-toxins or toxins retained within the cell. Among the pathogenic bacteria there are very few which secrete toxins when growing outside the body. Clostridium tetani or lockjaw bacillus, Corynebacterium diphtheriæ or the diphtheria bacillus, Clostridium botulinum or a bacillus causing a type of food poisoning, Pseudomonas pyocyanea or the blue pus bacillus are the most important. ”

“ It forms large terminal spores, whereas Klein’s bacillus formed no spores; (2) it will grow at a temperature of 34° F., while Klei bacillus did not grow below 50° F.; (3) it produces an acid reaction in culture media, while Klei bacillus gave a distinctly alkaline reaction; (4) it will grow on the ordinary nutrient media—gelatin, agar, and broth—without the addition of glucose, while Klein’s bacillus did not; (5) it peptonizes the casein in milk, whereas Klein’s bacillus had no action on milk ”

“ In old artificial cultures chains of considerable length may be formed. In the blood the bacillus is usually found in the leucocytes, as many as 20 or more being often present in a single cell. In the lymph networks of organs they also invade the leucocytes but are found in free masses as well. The bacillus is anærobic, but facultative ærobic, its preference being manifestly for the absence of oxygen. ”

“ A test is made for the number of bacteria, and a well of spring water which contains more than about fifty in a cubic centimeter is a suspicious water. Surface water, on the other hand, may contain two or three hundred without being necessarily bad, the types of bacteria being harmless. Generally, a chemist will also determine the presence of the colon bacillus which is found in the intestinal tract of man or warm-blooded animals. ”

“ The germ which causes this fever has generally been supposed to be the bacillus of Eberth. More recent bacteriological studies rather indicate that the bacillus coli may also cause the disease. These germs are usually carried into the body in food or drink, and, lodging in the small intestines, begin to grow and multiply, and by their life produce poisonous ptomaines which are absorbed and carried by the circulation to all the organs and tissues of the body. ”

“ Desmo-bacteria (or bacilli) are rod-like organisms, occurring of various lengths and different thicknesses. In a slide of the bacillus of tuberculosis and anthrax, we notice at intervals dots which represent the spores from which, as the rods break up, future bacilli are developed. ”

“ Animal experiments have shown that both meat and milk derived from tuberculous cattle are capable of conveying infection. The precise degree of danger to human beings from the use of these foods under modern conditions is still in dispute. Since the tubercle bacillus of bovine origin differs from the tubercle bacillus of human origin in certain well-defined particulars, it is possible by careful study to distinguish the human infections caused by the bovine bacillus from those caused by the so-called human tubercle bacillus. ”

“ Further, that a number of our most dangerous disease germs, like the typhoid bacillus, the bacillus of tuberculosis, and the bacillus of diphtheria, have almost perfect "doubles," law-abiding relatives, so to speak, among the germs that normally inhabit our throats, our intestines, or our immediate surroundings. The ultimate foundation question of the science of bacteriology is, How did the disease germs become disease germs? ”

“ That this bacillus was the cause of the outbreak was subsequently shown by the fact that the serum of blood taken from some of the patients showed characteristic clumping with a pure culture of this bacillus, just as happens with the blood of a patient suffering from enteric fever when a cultivation of the microbe of this fever is mixed with it (see page 301) . In this outbreak the symptoms were usually diarrhœa, vomiting, intense thirst, desquamation of the skin, and a slow convalescence, lasting from three to six weeks. (See page 26 for poisoning by Bacillus enteritidis sporogenes.) ”

“ As a matter of fact, Bacillinum contains in its elements everything that a cavity of a tuberculous lung is capable of containing; that is to say, many other things besides Koch's bacillus. The bacillus of Koch is feebly pyogenetic, and the purulent contents of the cavities include pyogenetic staphylococci and streptococci, to say nothing of the organic products which play a large part in the production of the hectic fever of tuberculosis. It is a combination of toxins, then, which constitutes Bacillinum, and especially of toxins of a purulent nature. ”

“ The qualitative discrimination of the bacteria present in dust has resulted in the discovery of, amongst other disease germs, the consumption bacillus, the lock-jaw or tetanus bacillus, bacteria associated with diphtheria, typhoid fever, pulmonary affections, and various septic processes. ”

“ Others, on the contrary, are, as we have seen, from birth unusually susceptible. This inherited susceptibility to the incursions of the tubercle bacillus, should this find lodgment in the body from without, by no means always reveals itself in any apparent lack of vigour or robustness of the body. Still, any habit or mode of life which diminishes the bodily vigour, whether in those predisposed to this malady or in the apparently immune, and gives it a leaning toward disease, diminishes, as a rule, the chances of a successful contest with the bacillus. ”

“ In my own laboratory, recent experiments made with the bacillus of glanders have shown that when grown in a slightly acid medium containing alkali-albuminate, albumoses, peptones, and crystalline bodies such as leucin and tyrosin are formed in considerable quantities. Kresling162 has reported similar results. With the tubercle-bacilli, many like results have been recorded. Thus, among others, Crookshank and Herroun163 have reported the finding of albumoses, peptone, and a ptomaine when the bacilli have been grown in glycerin agar-agar, and also in fluid media. ”

“ Having glanced hastily at the history of bacteriology, we may next consider some facts concerning the germs themselves. What are they? To the lay mind the words germ, microbe, bacterium, and bacillus often convey confused ideas of invisible, wriggling, worm-like creatures, enemies of mankind, ever on the watch to gain a stealthy entrance into our bodies, where they wreak harm and death. Scientifically considered, however, they are the smallest of living things yet known. They are not animals, but are members of the vegetable kingdom, and are possessed of definite yet varying shapes. ”

“ We may say, then, that the effect the bacillus has on the host depends largely on the host. Not only does it depend on what the host is, but the particular condition of the host at the time of infection is of importance. Children are subject to many diseases that adults seldom have. Hunger, thirst, fatigue, exposure and other factors may make a person susceptible to the actions of certain bacteria that would be harmless under other conditions. ”

“ If the culture is too old the spores will all be free outside the rods, while if too young they will decolorize with the acid. For Bacillus subtilis and Bacillus anthracis, cultures on agar slants forty-eight hours in the 37° incubator are just right. For the spores of Clostridium tetani, the culture should be three days old, but may be as old as a week.
Staining of “Acid-fast” Bacilli.—Mycobacterium tuberculosis, Mycobacterium of Johne’s disease, “grass” and “butter bacilli,” Mycobacterium lepræ, Mycobacterium smegmatis. ”

“ When it invades the muscle tissue proper, it follows along the sarcolemma sheaths between the muscle fibers. As a result of this growth the muscular tissue becomes softer and tends to break more easily.
4. The bacillus belongs to the class of putrefactive anaerobes which are widely distributed in nature in dust, soil, and excrementitious matters. The bacillus or its spores is present in the dust and dirt of packing houses and finds its way into the hams in the various manipulations to which they are subjected. ”

“ No sporeless bacillus is known which can survive through drying.
2. That tubercular matter and cultures survive temperature up to 100° C. Non-spore-bearing bacilli and micrococci are killed by being exposed for five minutes to a temperature of 65–70° C., whereas spores of other bacilli withstand much higher temperatures.
3. Tubercular sputum distributed in salt solution does not lose its virulence by being kept at 100° C. for one or two minutes; sporeless bacilli certainly would (Klein) . ”