Enemies of Bacteria

ENEMIES OF BACTERIA By Dr. J. E. Greaves, Utah Agricultural College The surface of the earth is limited as are also the elements essen- tial for the growth and normal functioning of plants and animals. Furthermore, some plants and most animals are so constituted that they require their food in the form of definite compounds. Such plants and animals must obtain their food from the body of other plants and animals. These conditions have given rise to a constant struggle for existence. It manifests itself among members of the same species; even man competes with man for a place "in the sun." Species struggle with species, the higher preying upon the lower, all down the line. Even the little amoeba devours the still smaller bacterium. The bacterium situated at the bottom in the scale of life returns the com- pliment, up the scale, with a vengeance. This is true to such a degree that the bacteria are the greatest destroyers of all. They stand as the link between the living and the dead; acting as if they were the time- keepers in the race and fight of life. When the higher plants and ani- mals have had their borrowed material which compose their body, for their allotted time, the bacterium intervenes, ends the race, and returns the elements to the great earthly reservoir of supply so they can be used over and over in the neverceasing drama of life. In this scheme of things it appears as if bacteria stand apart from other forms of life inasmuch as they have no smaller organisms to prey upon them. Due to their method of multiplication they never grow old; hence, barring accidents, they may be considered to be im- mortal. It is even likely that they were the first life upon this planet, as some of them can subsist upon the bleak rock watered with the rain, and receiving their energy from the traces of nitric acid which it contains. While it is true that the single-celled forms of life never grow old and are therefore not subject to natural death, yet there are many facts which have recently been brought to light that indicate that bacteria do not hold that enviable position of being free from the attack of smaller microorganisms. Briefly this has come about as follows: Haukin, in 1896, found that the waters of India purify them- selves. The Jumna River at Agra contained 100,000 bacteria per cubic centimeter, while three and one-half miles below it contained only ninety bacteria. It is a well-known fact that these rivers are highly polluted, yet the disease-causing bacteria quickly disappear from them. This is not due to a poison, for none is to be found in them. It is probably something which is alive, for heat destroys it. Whereas cholera organisms quickly disappeared from these natural

ENEMIES OF BACTERIA 431 waters, they actually multiplied in the same water after it had been boiled. Haffkin, who was in charge of a laboratory where plague vac- cine was produced, noticed that some of the cultures of the plague bac- teria grew normally for a time, then they would disintegrate and all the plague-producing microbes disappear. This was such a common occurrence that the workers gave to them the name of "suicides." Why did they commit suicide? What was the weapon used in self- destruction if it was a suicide? Today we are told that these were not suicides but still smaller microbes were preying upon them. In 1915 D'Herelle, of the Pasteur Institute, had under observa- tion an adult, suffering with a severe case of dysentery. Each day a small amount of the feces was placed in a steril tube or bouillon. After incubation at 3 7° for over night, the growth was filtered through a clay filter which removed all, of the dysentery bacilli. This clear filtrate was added to a second tube to which had been added previously the dysentery bacilli. The tube was incubated, and at the end of twenty-four hours the bouillon was cloudy, due to the great number of bacteria which had grown within it. This procedure was repeated daily, when one day, it was found upon examining the tubes prepared the day previously, there was no growth. If a drop of this was car- ried to another tube, it prevented growth in this tube, even though the beef tea had been previously heavily seeded with the dysentery bacteria. After considerable work of this nature, D'Herelle suggested that in the filtrate was a living organism that grew as a parasite upon the bac- teria and destroyed them. To this he gave the name of bacteriophage, meaning bacteria-eaters. Thus, fulfilling the philosophic words of the poet: "Great fleas have little fleas upon their backs to bite 'em And little fleas have lesser fleas, and so ad infinitum. And the greater fleas themselves, in turn, have greater fleas to go on, While these again have greater still, and greater still, and so on." Having learned that there is a something which preys upon bac- teria, many a question comes to the fore: How large are they? Is it possible to see the bacteriophage even with the most powerful micro- scope? Can they be counted? What do they feed upon? How do they multiply? Are they different species? If so, do they all attack the bacteria with the same vigor? Can they be used by man to combat the disease causing microbes which attack him? These and many other questions have been asked, and some of them have been answered. Although the bacteriophage cannot be seen even with the aid of the most powerful microscope, yet they have been measured. This is done by passing them through filters the size of the pore of which have been determined. If they pass through one filter of a definite size but not through another just a size smaller, it is known that in size they must be between the two. By this means it has been found

432 IMPROVEMENT ERA that the bacteria are many thousand times larger than the bacteriophage. Bacteria average about one-twenty-five-thousandth of an inch in length; therefore, the bacteriophage are less than a thousandth this size. It requires five hundred million bacteria to weigh one milligram. It would require many thousand times this number of bacteriophage to weigh this much. It is probable that bacteria are as much larger than the bacteriophage as a fly is larger than the bacteria. These values approximate that of the protein molecule. It ap- pears to leave us in a dilemma; as proteins have been looked upon as the basis of life. Hence, is it possible to have living organisms smaller than the protein molecule? An organism is looked upon as a cell or an aggregate of cells, and a cell as a mass of protoplasm containing a nucleus; and protoplasm is a complex of proteins. When we learned of the bacteria we came to define a cell as a mass of protoplasm con- taining nuclear material. Therefore we omitted the idea of an organ- ized nucleus. It may be that our concept of the cell will have to be modified so that our description of a living organism may be defined as a micella which is composed of material more simple than the pro- tein. Moreover, as recently suggested by Dr. C. B. Lipman, it may be that life originated with very simple compound and not with the complex protein molecule. The bacteriophage cannot only be measured, but they can be counted and their speed of multiplication followed. The procedure is very similar to that used in the counting of bacteria. The number of bacteria in any substance is found by diluting with a measured volumn of sterile water. The well-diluted material when in the liquid state is poured into some sterile solid media. On solidifying, the bac- teria are fixed on the surface and grow until they become so numerous that they may be seen with the naked eye; just as a clump of trees can be seen in the valley from the mountain-side, whereas a single tree may be overlooked. It can be assumed that each group developed from a single microbe; hence, knowing the dilution one can calculate the number of bacteria in the original sample by counting the number of such colonies and multiplying by the dilution. If measured volumns of the substance to be studied are seeded into heavy cultures of bacteria and then pouring onto a solid medium, the bacteriophage can be counted as bacteria, free from the bacteriophage, multiply and soon become visible. But where the bacteriophage are present the bacteria do not grow; hence, we have a bare space on the culture media. One can ascertain the number of bacteriophage present by counting the bare spots on the medium. In this manner it has been learned that some bacteriophage are found in soil, some in water, and others in the alimentary canal of man and lower animals. Furthermore, we have learned that they multiply more rapidly than do bacteria. They grow only in the body of bacteria, and when from eighteen to twenty-five are present in the body of the bacterium it explodes; the

ENEMIES OF BACTERIA 433 bacteriophage are liberated and seek other bacteria on which to prey. Just as Pasteur found it possible to increase the destructive powers of bacteria by successive passage through the bodies of susceptible animals, likewise D'Herelle has found it possible to increase the killing power of the bacteriophage for bacteria by successive cultiva- tion in the body of bacteria. By this means many strains have been produced which quickly devour the typhoid, diphtheria, dysentery, and other disease producers. Moreover, these highly active strains are found in the bodies of individuals recovering from these diseases; whereas, when the disease terminates fatally they are usually absent. Hence, they are probably often the determining factors in recovry. Therefore, we find that bacteria have their diseases as has man. We are prone to wonder if the bacteriophage in turn have still smaller organisms which prey upon them and, will science develop strains of the bacteriophage which can be liberated in water and thus free them of harmful microbes? Will the physician of the future combat the com- municable diseases of man by the use of virulent bacteriophage which will prey upon the disease-causing bacteria? Will it be possible to make community "catching" as is now the case with disease? The indications are that it will. Time alone will answer. Logan, Utah. Hymn Ye saints, no cheap salvation Can satisfy your souls; For you no heav'n telestial Eternal joy controls; Though "pearly gates" and mansions Of rest, God's love assures, Their glories fade to anguish With Father's home not yours. From sacrifice, then, shrink not A higher heav'n to own, Where Father, Mother, Brother Can share with you their throne; Where Gods shall be your helpers While angels do your will, Eternal progress guiding, The goal, perfection still. Salvation such, celestial, Is yours who pay its price — Accept God's own true gospel, (No substitutes suffice) , Then, daily live its precepts, Serve God with heart and hand; O! pay its price with gladness And in his presence stand. Thatcher, Arizona C. E. RICHARDSON

Photo by Geo. Ed. Anderson. MEMORIAL TO ESCALANTE The above monument is prominently located in Spanish Fork, Utah, the plate containing the following inscription: Escalante, a Spanish Priest, the first white man to look upon this valley, camped with his comrades beside the Spanish Fork, September 23, 1776. Placed to perpetuate the memory of that event by the Spirit of Liberty Chapter, Daughters of the American Revolution, and the City of Spanish Fork, 1922. "Though the Pathfinders die, the Paths Remain Open."