Laboratory method

“ 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. ”

“ On reaching the laboratory, the method of examination consists in adding measured quantities of the water sample to several tubes of nutrient media previously liquefied by heat, pouring plate cultivations from each of these tubes, incubating at a suitable temperature, and finally counting the colonies which make their appearance on the plates.
Apparatus Required:
Plate-levelling stand. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ An accredited analytical laboratory should be used to conduct analysis of collected samples, and it is essential to consult with the analytical laboratory before sampling to ensure that the measurement methods available can meet the defined sampling needs. ”

“ 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. ”

“ So at about the time when the microscope had taught that the cell is the really essential structure of the living organism, the chemists had come to understand that every function of the organism is really the expression of a chemical change—that each cell is, in short, a miniature chemical laboratory. ”

“ 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. ”

“ 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. ”

“ The laboratory experiments should be both qualitative and quantitative in character. They should on the one hand illustrate the peculiar properties of the substances studied and the typical concomitant changes of chemical action, but on the other hand a sufficient number of quantitative exercises in the laboratory should be introduced to bring home to the student the laws of combining weights and volumes, thus giving him the idea that chemistry is exact and that quantitative relations always obtain when chemical action takes place. ”

“ A more precise conception of the nature of the proposed laboratory may be formed if reference is made to certain groups of appliances which such a laboratory should possess and be able to place at the disposal of the scientific men coming to it for facilities which may be denied them at home. ”

“ From these considerations it must be evident that the usefulness of the physical laboratory can not be inferred from the benefits derived from the laboratory teaching of chemistry, but must be judged by a scale of values peculiarly its own. We have called physics an exact science. ”

“ Experiments [292] of this class—those in which measurement of some kind is involved—are the proper work of a physical laboratory. In every experiment we have first to make our senses familiar with the phenomenon; but we must not stop here—we must find out which of its features are capable of measurement, and what measurements are required in order to make a complete specification of the phenomenon. We must then make these measurements, and deduce from them the result which we require to find. ”

“ Under the head of "observations which lead to the theory that all matter is made up of very small separate particles" are embraced experiments on solution, diffusion, and the pressure of gases. A number of chemical experiments are given in a chapter devoted to "investigation of the composition of various kinds of matter." The final division comprises experiments in optics, designed to lead to the theory of the ether. An appendix gives many practical hints in regard to conducting the work in the laboratory. ”

“ I found it impossible to secure the necessary privacy here, and, before opening my experiments, I selected a site for a new laboratory in an unfrequented spot among the mountains this side of Lake Tahoe. You will be the first man, with the exception of my two devoted assistants, to see my apparatus, and you shall share the sensation of the critical experiment. ”

“ Its research presents the historical or phyletic standpoint, and tends to consider the entire adult organism without attempt at abstraction of particular qualities. There is the laboratory proper, at university or marine or fresh-water or experiment station, that digs into the inside of the animal with the microscope, that tries to trace its whole development, that attempts to reduce its processes to known physical and chemical factors. ”

“ 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. ”

“ The minimum data entered in the notebook should be sufficient to enable another chemist to derive the same results as the original worker, with no other source of information. In addition to this minimum data, any other facts appropriate and pertinent to the sample analysis are to be entered. A chemist's notebook is always subject to inspection by his colleagues, supervisors, or inspectors from outside the laboratory. ”

“ There was then no occasion for those delicate instruments of precision which are now found in every physical laboratory by means of which the man of science is able to investigate phenomena and determine laws that were quite unknown until a few years ago. ”

“ Probably not a man of us in the whole senior class had any idea of a chemical laboratory save as a sort of small kitchen back of a lecture-desk, like that in which an assistant and a colored servant prepared oxygen, hydrogen, and carbonic acid for the lectures of Professor Silliman. ”

“ Each is in its way a chemical laboratory indispensable to the right conduct of the organism, but the precise nature of its operations remains inscrutable. The vast importance of the operations of these intermediate organs is unquestioned. ”

“ Professor Schäfer expressed the opinion, anticipated and shared by many other investigators, that the progress of chemical experiment renders it probable that further steps, culminating in the successful construction of "living" matter in the laboratory, are not beset by any insurmountable obstacles and will sooner or later be accomplished. ”

“ The experiments which were detailed in the Bakerian lecture read during the absence of Davy on November 15, were made in July and August.
On August 30, after entering things wanted, he wrote in the Laboratory Book:
‘No experiments are to be made or carried on in the laboratory without the consent and approbation of the Professor of Chemistry. The attempt at original experiment, unless preceded by knowledge, merely interferes with the progress of discovery. ”

“ That in a chemical laboratory there is no appliance so sensitive as a diseased nerve, does not argue the inefficacy of the atomic dose, but proves the want of adaptation of the chemical apparatus to deal with the subject. ”

“ 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. ”

“ It is thus possible to measure the induced molecular change by measuring the correlated variation of any of the properties described above. The choice of a particular method will be governed by special convenience under given conditions. ”

“ The results of Leslie and Rumford were obtained in the laboratory; but the walls of a laboratory do not constitute the boundary of its results. Nature's hand specimens are always fair samples, and, if the experiments of the laboratory be only true, they will be ratified throughout the universe. ”

“ 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. ”

“ One has but to ascend another flight of stairs to pass out of the sphere of the microbe and enter a department where attention is directed to quite another field. We have now come to what may be considered the laboratory of hygiene proper, since here the investigations have to do directly with the functionings of the human body in their relations to the every-day environment. Here again one is struck with the meagre equipment with which important results may be attained by patient and skilled investigators. In only one room does one find a really elaborate piece of apparatus. ”

“ The technique of the organic chemical laboratory is a considerable and somewhat intricate body of knowledge. Through oral instruction the student becomes acquainted with those devices and forms of apparatus required for common operations, getting, where there is a choice of processes, the one which his instructor has had the best success with. ”

“ The laboratory building is a fireproof structure of light gray brick and limestone, commanding a beautiful view of the East River and the country beyond. There are laboratories of pathology, bacteriology, chemistry, physiology, pharmacology, experimental medicine and experimental surgery, each of which is under the charge of a member or associate of the institute with a staff of assistants. ”

“ In this insistence that the chief use of the physical laboratory is instruction in the difficult art of physical measurement, an art difficult on the technical side, because of the patience and manipulative skill required, and difficult on the intellectual side because the comprehension of many measuring instruments is dependent upon advanced theory and considerable analytical power, it has not been forgotten that the laboratory may serve certain other though perhaps minor purposes. ”