Laboratory manual

“ The microscope required for bacteriological studies should be perfect in all its parts. With regard to the choice of an instrument, it is very much a matter of price, since the most perfect is usually the most costly; I shall therefore proceed to give a typical example of the instrument in use in a bacteriological laboratory. The microscope should possess the following qualifications, all of which are absolutely necessary for the study of such minute objects as bacteria and other micro-organisms. ”

“ A station for experimental biology must have not only the proper equipment for breeding and rearing organisms under natural conditions, but also for artificially changing and controlling the external factors of the environment. The physico-chemical laboratory (Fig. 10) provides the substances used as variable external factors and also to determine the physico-chemical properties of the biologically important colloids. ”

“ The large general laboratory has fifteen working places fitted with all the usual optical and histological apparatus and reagents. The necessary conditions for the study of the influence of mechanical agencies are enough light, as little dust and infectious material as possible and sterilizing flames. One line of research is to subject organisms to the influence of different densities in the surrounding medium. For fluids there are basins containing different concentrations of salts, brackish water, etc., with an areometer for measuring the specific gravity of each of the various liquids. ”

“ There is, indeed, little to see that would greatly interest the casual inspector, for in its outward aspects one laboratory is much like another, a seeming hodgepodge of water-tanks, glass jars of specimens, and tables for microscopes. ”

“ Following manufacturer's instructions for this procedure, adjust readout meter to agree with the calibration standard.
NIOSH Manual of Analytical Methods (NMAM) , Fourth Edition, 8/15/94 OXYGEN: METHOD 6601, Issue 2, dated 15 August 1994 - Page 3 of 3 6.
Practice routine instrument maintenance. a. Check sensor cell diffusion barrier for dirt and moisture. Clean with a soft cloth or tissue if needed. b. Replace sensor cell every six to nine months with average use. NOTE 1: Store cell in nitrogen when not in use to prolong life. ”

“ Now, my good friend, your living body, and my own, are laboratories, in which changes of precisely the same kind are constantly brought about; your living body, and my own, are made of an enormous quantity of separate chambers and vessels, very small, it is true, but nevertheless such as can be seen quite distinctly when they are looked for with the microscope. In these small chambers and vessels different kinds of substances are thrown together, exactly as the zinc, and acid, and blue vitriol are in the laboratory-chambers of the electric telegraph. ”

“ Enough has been said to show distinctly the main points in favor of a laboratory specially endowed for research, and some of the chief considerations which must arise in its establishment. Such a laboratory as is here indicated, a laboratory in which many specialists could combine forces in the more difficult fundamental investigations of physical science, surely ought not to remain long a mere fabric of the imagination, a misty dream of the future. It should be founded—whether by an individual or by the nation it matters little. ”

“ In such a statement there is not, however, intended the faintest suggestion that work in the physical laboratory is anything but useful and necessary, but rather to emphasize how widely the function of the physical laboratory differs from that of the chemical and biological laboratories. Physics is an exact science (though just what that means can be learned only in a physical laboratory) while biology is not so at all and chemistry is but to a limited degree. ”

“ Every instrument of precision used in the laboratory should be a standard of its kind, the best which could be made; otherwise the work of the institution might fall short of the high character intended for it. So also with the chemicals: only the best should be tolerated. ”

“ One of the most important innovations in this line has been the incorporation into the regular courses of a system of laboratory work, by means of which each student is given facilities for the actual chemical and microscopic study of the proximate principles, the elements entering into the composition of the human body and its secretions, and the reactions and histological characteristics produced by various pathological conditions, which are of value in diagnosis. ”

“ The physical state of the analyte (i.e., gas, aerosol, vapor, or combination thereof) plays an important factor in the selection of an appropriate sampler. Analytes which can exist in more than one physical state may require a combination of sampling media in one sampler for efficient collection [1] . Where possible, commonly available and easily used samplers should be investigated initially. As the preliminary testing of a sampling method progresses, further modification in the sampling medium or sampler design may be required and may affect the measurement procedure. ”

“ The method should have guidelines for interpretation of collected data. Such guideline are discussed in Interpretation of Results below.
7. To minimize the risk of harm to workers, when two biological monitoring methods will provide the same information, the less invasive method should be used. Thus, methods monitoring urine or exhaled breath are preferred over those monitoring blood.
Sampling Strategy. Strict attention to specimen handling and collection is essential for quality data. The analytical laboratory should be consulted for sampling instructions. ”

“ Given an unlimited quantity of a substance for testing purposes it is not always easy to determine its composition. With very small quantities, perhaps less than a tea-spoon full in all, the difficulties of the analyst are increased tenfold and without the assistance of the microscope his efforts would be unavailing, he deals in drops and every drop is precious. Sad to relate this form of testing, known to science as micro-chemical analysis, has been practised to a far greater extent on the continent than in this country. ”

“ Inject known volume of N 2O into the sample cell with a gas-tight syringe. NOTE: Inject the N 2O through tubing or a septum attached to the sample cell. c. Calculate concentration, C s (ppm) , of N 2O in sample cell:
d. When instrument reading stabilizes, record meter or recorder deflection. e. Prepare calibration graph (C s vs. meter or recorder deflection) . Practice routine instrument maintenance. a. Replace septa in a closed-loop system frequently in accordance with manufacturer's recommendations. b. Check and replace, if cloudy, the NaCl windows in the infrared spectrophotometer. ”

“ This process of calibration is particularly important in laboratory research, where the observer has frequently to make his own apparatus, and cannot afford the time or outlay required to make special tools for fine work, but is already provided with apparatus and methods of accurate testing. For non-scientific purposes it is generally possible to construct instruments to measure with sufficient precision without further correction. The present article will therefore be restricted to the scientific use and application of methods of accurate testing. ”

“ Aspirate a standard for every 10 samples to check instrument drift. Check analytical recoveries with at least one spiked media blank per 10 samples. Use method of additions occasionally to check for interferences. ”

“ To this end, the laboratory experimental work follows as closely as possible after the classroom exercises so that the essential unity of the two may be impressed upon the student’s mind. An effort is made to develop the student’s capacity for sustained careful observation and deduction, and to initiate good practice in the matter of recording and reporting upon scientific and engineering data. Great stress is placed upon the precision of the results obtained in the laboratory. ”

“ According to the directors, about seventy-five investigators have made use of the laboratory since its foundation and something like six hundred and fifty students of various grades have received instruction. Regular class instruction is given each summer by university professors from the departments of zoology, botany and physiology. Although the buildings are not formally open during the rest of the year, investigators are usually able by special arrangement to get the use of the laboratories at almost any time. ”

“ In the classroom the principles underlying the laboratory work are studied; additional methods also are considered. Throughout the year the student receives training in the calculations of analytical chemistry, with special attention to the errors of measurement. Particular consideration is given to the accuracy of the methods studied, in connection with the requirements of their use, and to the saving of time by proper planning of work and choice of method.
Texts: Kolthoff and Sandell, “Textbook of Quantitative Inorganic Analysis”; Giesy, “Problems in Quantitative Analysis”. ”

“ The man test laboratory described above provides facilities for obtaining information concerning the efficiency of canisters, facepieces, etc., within very short periods of time, without waiting for the construction of special apparatus required for machine tests. To get satisfactory results from machine tests, a delicate qualitative chemical test for the gas is essential. Man tests can be made when such a qualitative test is not known. Further, man tests can be made with higher concentrations of some gases than is practicable with machines. ”

“ In a large diagnostic laboratory, or in one intended for teaching and investigation, there are numerous accessories necessary to modern microscopic technique. For the observation of living objects a warm stage is needed. The simple electrical apparatus devised by Ross is the most convenient form, as it can be slipped on and off the slide without changing the focus. ”

“ Filter all samples, eluents, and water flowing through the ion chromatograph to avoid plugging system valves or columns. Transfer a portion of sample solution to a syringe fitted with an inline membrane filter, for direct injection or for transfer to autosampler vials. Inject 50-μL sample aliquot. For manual operation, inject 2 to 3 mL of sample from syringe (through inline filter) to ensure complete rinse of the sample loop. Measure peak height. If sample peak height exceeds the linear calibration range, dilute with eluent, reanalyze, and apply the appropriate dilution factor in calculations. ”

“ Besides the large laboratories for general chemistry and analytical chemistry, there are smaller laboratories for volumetric analysis, for organic chemistry, for sanitary chemistry with special reference to the analysis of water and air, for oil and gas analysis, for the optical and chemical examination of sugars, starches, etc., for the determination of molecular weights, and so on. In the industrial laboratories, the students are taught how to manufacture chemicals with due regard to emonomy of material, space and time. ”

“ These notes are examined at the time, or subsequently, by the teacher, and the pupil is not allowed to take the book from the laboratory; nor can he use any other book on Chemistry while experimenting. By this means he learns to make his own observations and inferences.
For the benefit of the science and the added interest in the study, it is earnestly recommended that teachers encourage pupils to fit up laboratories of their own at home. This need not at first entail a large outlay. A small attic room with running water, a very few chemicals, and a little apparatus, are enough to begin with ”

“ Before buying a microscope the student should obtain an illustrated price list from any of the firms mentioned above, and, having selected an instrument, he should test it very carefully, or better get some experienced friend to test it for him, before deciding to purchase it. Delicate test objects such as diatoms, scales of butterfly’s wing, or a stained specimen of micro-organisms should be employed. The coarse and fine adjustments should be tried. They should work freely and smoothly and without any delay. ”

“ His heart, which shows no signs of low temperature, is mainly in his laboratory, and he leads the way there, down a flight of stone steps to the basement, with a readiness that very clearly exhibits his latent enthusiasm.
THE LABORATORY OF DAVY AND FARADAY AT THE ROYAL INSTITUTION.
Moreover, it is a laboratory eminently calculated to excite the enthusiasm of anybody, being, in fact, the most famous laboratory known to chemical science. ”

“ Your lab notebook is part of the scientific legacy of your laboratory. Therefore, you need to protect your lab notebook. Paper lab notebooks should not be taken home. When you leave the laboratory each day, you should leave your lab notebook in a location where your research supervisor can find it. Ideally, you should lock it in the same place every day. If your research institution or lab supervisor allows, you will be able to make copies of your lab notebook, but the original belongs to the institution that paid your salary and handled your research funds. ”

“ The small quantities of sea water needed are brought to the laboratory from the nearby sea by hand. A good supply of glassware for experimentation on simple animals is always on hand.
As already indicated, the laboratory is operated in close connection, so far as research is concerned, with the department of physiology at Berkeley. No provision is made or is hardly possible for formal instruction or for any considerable number of investigators, or for much range of investigation. ”