Koch first described the beaded forms of the tubercle bacillus and regarded the beads as evidence of spore formation. Later investigators attempted to correlate the beaded forms with the age and the virulence of the microorganism. These studies, however, have not been fully confirmed. In the present paper, data will be submitted to show that the beads exhibited by tuberele bacilli stained with earbol fuchsin are greatly influenced by the preparation of the dve used, by the presence of electrolytes in the system, and 1y subsequent washing with alcohol and other organic solvents. EFFECT OF ELECTROLYTES A four-weeks-old culture of virulent tubercle bacilli, Strain H37, grown in Long's synthetic medium, was transferred to a Buchner filter, and the bacilli freed from the medium by washing with distilled water. The washed bacilli were ground in an agate mortar and then suspended in distilled water. Twenty films of tubercle bacilli were prepared by spreading one loopful of this suspension on clean glass slides. The films were air-dried. The solution of carbol fuchsin used in this experiment was prepared as follows: To 10 ml. of a saturated solution of pararosaniline hydrochloride (Lot i 9155 from the National Aniline Company Buffalo, N. Y.) in 95 per cent ethyl alcohol, there were added 10 ml. of alcohol and 180 ml. of 5 per cent aqueous phenol. This solution of earbol fuchsin was divided into two parts: A. 95 ml. carbol fuchsin + 5 ml. distilled water. B. 95 ml. carbol fuchsin + 5 ml. 10 per cent NaCl solution. Ten films were flooded with solution A (no salt) and ten films with solution B. The slides were heated in an electric oven at 90'C. for twenty minutes. The excess dye was poured off, the slides washed with acid alcohol for thirty seconds, and then thoroughly washed with distilled water and air-dried. On microscopic examination, the preparations stained with solution A (no salt) revealed the bacilli to be solidly stained, with a slight purplish tinge; no beads could be seen in the cellular bodies (fig. 1). On the contrary, the preparations stained with solution B (i.e., in the presence of NaCl in final concentration of 0.5 per cent) showed intense beading. In many, instances the beads within the bacilli gave the appearance of a chain of cocci. The beads were of a dark purplish color, whereas the cellular body itself was of a faint pink tinge. Each bacillus exhibited from I to 5 beads, irregular in distribution and of a diameter greatly exceeding that of the bacillus itself (fig. 2). This experiment was repeated and confirmed many times.
Determination 16 shows that tap water distilled from a residue from distilling sea water is only slightly heavier than ordinary tap water. Experiments 21 and 22 indicate that if tap water as purified contains an impurity it distributes itself equally between the phases when the water is frozen, which seems very unlikely. Experiments 19 and 20 indicate that if sea water as purified contains an impurity which increases its density it tends to stay with the ice rather than the liquid. I consider that these experiments prove that the difference in specific gravity is due to a difference in isotopic composition. SummaryPure water obtained from sea water has been found to have a specific gravity of 1.0000023 at 0 ± 0.0000002°c ompared with pure water obtained from Cambridge tap water at 0°.A convenient method of measuring small differences of specific gravity has been described.Cambridge, Mass.
There are several articles in the literature dealing with the subject of autolysis of the tubercle bacillus. AMcJunkin (1923) dehydrated living tubercle bacilli in 95 per cent ethyl alcohol for two minutes, suspended the microorganisms in oleic acid which contained a few drops of water, and incubated the mixture at 37°C. After several days, only a limited number of bacilli retained their acid-fast properties. The action was partially inhibited when the microorganisms were killed by heat or toluene. The experiments suggested to the author the "possibility that the solvent action was due to a thermolabile enzyme contained in the tuber
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.