variation in the solution for any given element will depend upon the total quantity absorbed, upon the concentration in the original solution, and also upon the volume of solution provided per plant. It is essential to differentiate between two sets of factors, the composition and concentration of the solution and the total quantities of the various elements present. The effect on the plant might be the result either of the concentration as found in the original solution, or of an insufficient total supply of one or more elements. In order to study the effects of concentration or of composition on plant growth, ideally a continuous flow of solution should be arranged so that the roots are always bathed in a solution of constant composition. Such a technique is ordinarily impracticable, and it is necessary to approximate the desired condition by providing a sufficient volume of solution per plant and by frequent changes. This is particularly true when the object of the investigation is to determine the relative effects of a series of solutions. To give a specific example, certain solutions may have only one tenth of their total concentration due to Ca (NO3). In such a case it is possible that all of the NO, might be absorbed before the solution was changed, or at least reduced to a very low level of concentration. Thus, if the interpretation of the experiment is based on three salt triangular diagrams, the effect, actually the result of insufficient NO,, might be correlated with a certain calcium magnesium ratio. In some experiments small bottles (250 to 400 c.c.) have been used with three to six plants in each bottle, changes of solution being made every three days, or sometimes only every four or five days. In the sand culture series the size of the jars usually permits the use of only 250 to 400 c.c. of solution per jar. In our experiments (to be described elsewhere) from 500 to 2,200 c.c. of solution per plant (barley) have been used, with changes every two or three days in many cases. Actual determinations of the absorption of each element have been made by analyzing the solutions or the plants. It has been found that under favorable conditions of light and temperature, more than 30 per cent. of the total electrolytes may be absorbed in three days, when 500 c.c. of a favorable nutrient solution of 2,500 p.p.m. concentration is provided for each plant. All of the elements are not absorbed in equal percentages, consequently not only the concentration but also the relation between the elements has been altered. In one experiment with solutions containing 100 p.p.m. NO, (500 c.c. solution per plant) barley plants six weeks old absorbed every trace of NO, from the solution in less than 72 hours. In several experiments in which plants have been grown in solution and sand cultures the yields of straw and heads are fairly comparable with those of plants produced in the field, where an excellent crop is obtained. In some sand and solution culture experiments reported the yield per plant has evidently been much inferior to that for similar plants grown in the soil for an equal period. Some limitation of light, temperature, aeration or of the nutrient solution must therefore have existed. In many cases there is a strong presumption that the supply of nutrients may have been deficient, as noted above. We do not desire, however to criticize any specific investigations. If plants are grown under sub-optimal light or temperature conditions, the total quantities of nutrients absorbed per plant may be much less than in our experiments. Moreover, in the first few weeks the plant has not reached its maximum power of absorption, so that short culture periods will require less quantities of nutrients. The point we desire to emphasize is that plants grown under the most favorable conditions may absorb or require much larger quantities of nutrients per plant than are ordinarily provided in sand and solution culture work. Each set of conditions should be tested by actual analysis of solutions and plants and results interpreted in terms not of the original solution alone, but also in terms of total supply and the varying condition of the solution in the periods between changes. It should also be noted that deficiencies in total supply in the earlier stages of growth may stunt the plant so that absorption in the later stages is much less than would occur with a normal plant. D. R. HOAGLAND DIVISION OF AGRICULTURAL CHEMISTRY, UNIVERSITY OF CALIFORNIA UNHEATED EGG-YOLK MEDIA FOR some years the writer has been using unheated egg-yolk media and has found them especially valuable in studying one of the foulbroods caused by an organism (Bacillus larva) which offers considerable difficulty in its cultivation. In a paper "Further Studies on American Foulbrood" to be published in the Journal of Agricultural Research reference is made to the employment of such media successfully in the study of this species. Believing that the fact might be of interest to those studying diseases caused by organisms for the cultivation of which unheated animal products are being employed and possibly also to those using heated egg media in their work, the technic used in the preparation of these media is given at this time. These are prepared by adding simply a sterile aqueous suspension of egg-yolk to the different media commonly used in the laboratory. The egg suspension is obtained as follows: After being disinfected the shell of the egg is broken the white poured off and the yolk dropped into a flask containing about 70 c.c. of sterile water. By agitating the flask a uniform suspension of the yolk material is obtained. This is then transferred to sterile tubes by pipetting, and stored until needed. On standing the suspension separates into a more or less translucent supernatant fluid and an opaque lighter yellow-colored sediment. In preparing the egg media about 1 c.c. of the egg-yolk suspension is added to each 5 c.c. of the base medium. If only the supernatant fluid is used a clearer medium will result. Egg agar has been the most useful of these media in the work referred to. The base should be at least 1.5 per cent. agar and after being liquefied should be cooled to between 45° and 50° C. before the suspension is added. Tubes may be inclined and stored until needed. The medium may be inoculated and plates made, or sterile plates may be poured. Although the pipetting of the sterile suspension rarely results in contamination of the media, if convenient to do so, it is well to test them for sterility after this step is taken. The egg suspension itself is a medium of some differential value. Eggs known to be recently produced are preferable for the egg-yolk suspension, although those obtained from the market labelled "strictly fresh" have usually been satisfactory. The shell is disinfected conveniently by immersing the egg in a suitable solution for a few minutes. A 1: 1,000 mercuric chloride one is satisfactory for the purpose. Alcohol and solutions of carbolic acid and formalin have been used but the latter two unless gloves are employed are unpleasant to the hands. After removing the egg from the solution, the shell is broken about one end and removed with forceps sterilized conveniently in the direct flame. The white being poured off the limiting membrane of the yolk is broken and the yolk material is poured into the flask containing the sterile water. The degree of transparency of the supernatant fluid depends somewhat upon the amount of water used in making the suspension. making the suspension. Occasionally contaminations are encountered. These are usually detected by changes in the appearance of the suspension following incubation. G. F. WHITE Cornell University Medical College in the City of New York Admits holders of baccalaureate degrees or sen iors who can present a degree at the completion of the first year. All students must have completed College courses in Physics, Chemistry, and Biology. Instruction by the laboratory method continued throughout the course. Classes divided into small sections facilitating personal contact of student and instructor. Clinical teaching concentrated in those services of Bellevue and New York Hospitals under direct control of Cornell. Additional facilities in other Hospitals. Graduate Courses leading to the degrees of A.M. and Ph.D. are offered in the scientific departments of the Medical College under the direction of the Graduate School of Cornell University. Session opens the last week in September and closes the second week in June. Fees including all College charges do not exceed $200 a year. For further information ană catalogue address Washington University School of Medicine REQUIREMENTS FOR ADMISSION Candidates for entrance are required to have completed at least two full years of college work which must include English, German, and instruction with laboratory work in Physics, Chemistry and Biology. INSTRUCTION Instruction begins on the last Thursday in September and ends on the second Thursday in June. Clinical instruction is given in the Barnes Hospital and the St. Louis Children's Hospital, affiliated with the medical school, the St. Louis City Hospital, and in the Washington University Dispensary. COURSES LEADING TO ACADEMIC Students who have taken their premedical work in Washington University, are eligible for the degree of B.S. upon the completion of the first two years of medical work. Students in Washington University may pursue study in the fundamental medical sciences leading to the degree of A.M. and Ph.D. Syracuse University College of Medicine Entrance Two years of a recognized course in arts or in science in a registered college or Requirements School of Science, which must include Physics, Chemistry, Biology, and French or German. Six and seven years' combination courses are offered. The First Two The Third Year The Fourth Year Course is clinical. Students spend the entire forenoon throughout the year as clinical clerks in hospitals under careful supervision. The clinical clerk takes the history, makes the physical examination and the laboratory examinations, arrives at a diagnosis which he must defend, outlines the treatment under his instructor and observes and records the result. In ease of operation or of autopsy he follows the specimen and identifies its pathological nature. Two general hospitals, one of which is owned and controlled by the University, one special hospital and the municipal hospitals and laboratories are open to our students. The afternoons are spent in the College Dispensary and in clinical work in medical and surgical specialties and in conferences. Summer School-A summer course in pathology covering a period of six weeks during June and July will be given in case there is a sufficient number of applicants. Address the Secretary of the College, 307 Orange Street THE LONG ISLAND COLLEGE HOSPITAL BROOKLYN-NEW YORK Sixty-first Annual Session begins September 22, 1919 The medical college requires two years of study in a college of liberal arts or sciences for admission. See specifications for Class A Medical Colleges by the Council on Medical Education, A.M.A.; also those for a Medical Student's Qualifying Certificate by the University of the State of New York. Conditioned Students not admitted For particulars address THE DEAN OF THE COLLEGE Brooklyn, SYRACUSE, N. Y, University of Alabama School of Medicine Mobile, Alabama Entrance Requirements The satisfactory completion of two years of study, in an institution of collegiate grade, to include Biology, Chemistry, Physics, and a reading knowledge of French or German. In addition to four year High School diploma. Combined Course The Combined Course which is now offered by the University in connection with its Medical Department gives to the student the opportunity of obtaining the B.S. and M.D. degrees in six years. This course is recommended to all intending students. The equipment of the school is complete. The clinical facilities ample. Eight full time teachers. For catalog and any desired information, address Tucker H. Frazer, M.D., Dean St. Anthony and Lawrence Sts., New York University of Georgia MEDICAL DEPARTMENT ENTRANCE REQUIREMENTS The successful completion of at least two years of work including English, Physics, Chemistry, and Biology in an approved college. This in addition to four years of high school. INSTRUCTION The course of instruction occupies four years, begin. ning the second week in September and ending the first week in June. The first two years are devoted to the fundamental sciences, and the third and fourth to practical clinic instruction in medicine and surgery. All the organised medical and surgical charities of the city of Augusta and Richmond County, including the hospitals, are under the entire control of the Board of Trustees of the University. This agreement affords a large number and variety of patients which are used in the clinical teaching. Especial emphasis is laid upon practical work both in the laboratory and clinical departments TUITION The charge for tuition is $150.00 a year except for residents of the State of Georgia, to whom tuition is free. For further information and catalogue address The Medical Department, University of Georgia AUGUSTA, GEORGIA WESTERN RESERVE UNIVERSITY School of Hygiene and Public Health SCHOOL OF MEDICINE ONLY MEDICAL SCHOOL IN THE CITY OF CLEVELAND ¶ Admits only college students and seniors in absentia. Excellent laboratories and facilities for research and advanced work. Large clinical material. Sole medical control of Lakeside, City, Charity and Maternity Hospitals and Babies' Dispensary. Clinical Clerk Services with individual instruction. ¶ Wide choice of hospital appointments for all graduates. ¶Fifth optional year leading to A.M. in Medicine. ¶ Vacation courses facilitating transfer of advanced students. ¶ Session opens Oct. 2, 1919; closes June 17, 1920 Tuition, $150.00. For catalogue, information and application blanks, address OF The Johns Hopkins University The second academic session will begin September 30, 1919. Opportunities for instruction and investigation will be offered in Bacteriology, Immunology and Serology, Protozoology and Medical Zoology, Epidemiology, Biometry and Vital Statistics, Sanitary Engineering, Physiology as applied to hygiene, including the principles of industrial and educational hygiene, Chemistry as applied to hygiene including the analysis of foods and the principles of nutrition, Social and Mental Hygiene, etc. The courses in these subjects are organized upon a trimestral basis and students may enter the School as candidates for a degree or as special students at the beginning of any trimester, fall, winter or spring. Men and women students are admitted on the same terms. For regularly matriculated students courses are arranged leading to the degree of Doctor of Public Health, Doctor of Science in Hygiene and Bachelor of Science in Hygiene. The details in regard to the requirements for matriculation in these courses are described in the catalogue of the School which will be forwarded upon application. A certificate in Public Health may be awarded to qualified persons after one year of resident study. Persons desiring to take one or more courses not as applicants for a degree may enter as special students on approval of the Faculty. For further information address the Director of the School of Hygiene and Public Health, Johns Hopkins University, 310-312 West Monument Street, THE REGISTRAR, 1353 East 9th St., Cleveland Baltimore, Maryland. Stanford University Northwestern University MEDICAL SCHOOL The Medical School of Leland Stanford Jr. University is an integral part of the University, and its Faculty controls the Lane Hospital which, together with the Lane Medical Library, is administered by the Trustees of the University. ADMISSION Three years of university instruction, including a year in Physics, Chemistry and Biology with laboratory work in each, and a satisfactory reading knowledge of French or German, are required for admission to candidacy for the degree of Doctor of Medicine. Three units of Organic Chemistry are also required for admission to the Medical School. INSTRUCTION The word in Medicine begins the first of October each year and closes about the middle of June. The first five quarters of the four years Medical instruction are given in the laboratories of the University at Palo Alto, California, the last seven quarters and the required interne year, in the Medical School in San Francisco, California. The degree of A.B. is granted upon completion of the first three quarters of the Medical curriculum, the degree of M.D. upon completion of the interne year. Students wishing to transfer from other institutions are advised to enter in the summer quarter, beginning the middle of June, in order to make up deficiencies. A Graduate Medical Course of six weeks is offered during the summer, and is open to all licensed physicians or graduates of recognised medical schools. GRADUATE COURSE TUITION The tuition fee is $50 per quarter for twelve quarters, payable at the beginning of each quarter. For information address THE DEAN of the STANFORD UNIVERSITY MEDICAL SCHOOL, Sacramento and Webster Streets, San Francisco, California. Medical School Situated in Chicago in close proximity to important Hospitals with an abundance of clinical material. Admission Requirements-Two years of College credit including a satisfactory course in Physics, Chemistry, Biology or Zoology, and French or German. Course of Study-leading to the degree of Doctor of Medicine-Four years in the Medical School and a fifth year either as Interne in an approved hospital or devoted to research in some branch of Medical Science. Graduate Instruction-in courses leading to the degree of Master of Arts or Doctor of Philosophy. Research Foundation-The James A. Patten Endowment for Research affords unusual opportunities for advanced students of Medical Science to pursue special investigations. Research Fellowships-Four fellowships of the value of $500 each are awarded annually to promote scholarly research. Tuition Fees-The tuition fee for undergraduate stu dents is $180.00 a year. For information address C. W. PATTERSON, Registrar 4231 South Dearborn Street Chicago, Illinois |