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Several letters to the editor are presented in response to articles in previous issues including "At Johns-Manville, it's back to basics," in the October 31, 1977 issue, "The problems with OSHA's cancer policy," in the October 24, 1977 issue, and "The President stumbles," in the October 31, 1977 issue.

Letters to the editor are presented in response to articles published in previous issues including "Raising the Cost of Frivolous Lawsuits" in the June 27, 1983 issue, "Post-Summite Blues Hit the Markets" in the June 13, 1983 issue and "Why the Big Banks Have Insurance Companies Shuddering" in the June 6, 1983 issue.

Several letters to the editor are presented in response to articles in previous issues including, "Computer stores: Tantalizing opportunity selling computers to consumers," in the September 28, 1981 issue, "Why planning fails," in the October 19, 1981 issue, and "El Salvador is just the fuse under a powder keg," in the October 12, 1981 issue.

Several letters to the editor are presented in response to articles in previous issues including "High-minded extortion" in the October 8, 1979 issue, "A "special" socialism that doesn't work" in the October 29, 1979 issue, and "Campaign politics rule economic policy" in the October 22, 1979 issue.

Complexes of benzophenone, benzophenone derivatives, or coumarin with alkali or ammonium iodides and iodine have been prepared and their conductivities studied. The organic sub-lattices involve six- or four-coordinate cation clathrated by the carbonyl compounds. The iodine sub-lattices consist of In chains in which I3- and I5- ions can be identified. AC (1 KHz) conductivities at room temperature vary from 10-1 to 10-6 Ω-1 cm-1, and are of a mixed ionic and electronic type. The most likely transport mechanism involves hopping processes in the polyiodine sub-lattice.

The performance of laboratories enrolled in three of the Centers for Disease Control microbiology performance evaluation programs was studied in relation to the number of actual patient specimens tested by the laboratories. Laboratories were grouped according to the number of specimens tested weekly to compare performance among the groups. Results of the study showed that laboratories, as a group, that tested large numbers of specimens performed better than laboratories that tested small numbers. The infrequency of performing certain tests or identifying certain microbial species can be an important factor in laboratory error. One strategy for laboratories that cannot resolve internal problems associated with low testing volumes would be to limit their testing to procedures that are done well.

In response to a need for monitoring the proficiency of public health laboratories in isolating and identifying Neisseria gonorrhoeae, a national external quality control program was developed. Essentially, three types of freeze-dried samples, representing different levels of challenge for identification, were sent to laboratories for testing. The quality of the samples was confirmed by external reference laboratories, and stability of the samples was confirmed by thermal degradation tests before the samples were sent to laboratories enrolled in the program. By analyzing laboratory results, we identified common errors and chronic problems in testing samples. As a group, laboratories testing small numbers of actual patient specimens did not perform as well in the program as did laboratories testing large numbers of specimens; however, the performance of laboratories testing small numbers of specimens improved over time. Overall, laboratories experienced the most difficulty with samples containing N. gonorrhoeae mixed with other microbial species. Laboratories that performed confirmatory tests committed fewer errors than did laboratories that performed presumptive tests only, but the failure to use pure cultures of gonococci for inoculation of cystine tryptic digest agar appeared to be a chronic problem in confirmatory carbohydrate testing. A review of the use of different plating media and confirmatory tests showed that the use of certain media and tests changed over time.

This report presents a summary and analysis of data from the Centers for Disease Control performance evaluation program in bacteriology for the 6-year period 1980 to 1985. During this period, the number of laboratories enrolled in the program ranged from about 750 to 1,000. Identification results reported by participating laboratories for representative species of six major groups of bacteria were placed into five response categories that were based on the level and accuracy of the identifications. Data on the performance of participants with bacterial groups and performance with selected species within each major group were analyzed. Overall, participants experienced the least difficulty in identifying species or serogroups of members of the gram-positive and gram-negative cocci. Participants encountered greater difficulties with anaerobes, gram-positive bacilli, and miscellaneous gram-negative bacteria. Identification of members of the family Enterobacteriaceae was of moderate difficulty. Problems in identifying certain bacterial species were probably related to a number of factors such as the characteristics of the species, its frequency of occurrence, the state of technology available for identification, and the state of proficiency and quality control in individual laboratories at the time of testing. Examples are given of improvements over time in the identification of certain bacterial species. Laboratories participating in an external proficiency testing program should take full advantage of the benefits of participation by instituting measures to correct testing deficiencies identified by the program.

In 1976, the Center for Disease Control initiated an external quality control program for the isolation and identification of Neisseria gonorrhoeae. This program required microbial samples of sufficient stability for shipment to laboratories throughout the United States. The Centers for Disease Control undertook studies to determine the most appropriate media for the propagation of strains for freeze-drying, the cell-suspending media that would afford protection during and after freeze-drying, the most favorable growth conditions, the proper times and methods for harvesting cells, the appropriate lyophilization conditions, the critical residual moisture content, and the stability of samples. These studies resulted in the development of methods for preparing and testing freeze-dried samples suitable for shipment.

Several letters to the editor are presented in response to articles, including "Big Trouble at Allegheny," in the August 11, 1986 issue "A Higher Cost of Giving Is No Cause for Low Spirits," by Gary Becker in the August 11, 1986 issue, and "Measuring the Rise in Part-time Employment," in the August 18, 1986 issue.

Several letters to the editor are presented in response to articles in previous issues including "Will Japan really change," in the May 12, 1986 issue, "From coast to coast, the push is on to limit liability," in the April 28, 1986 issue and the "Tax reform that makes sense," in the May 19, 1986 issue of the journal.

Several letters to the editor are presented in response to articles in previous issues including an article about the net operating income for Philadelphia National Corp. in the April 17, 1978 issue, "A genetic defense of the free market" in the April 10, 1978 issue and "BP is turning sour on the Alaska pipeline," also in the April 10, 1978 issue.

This section presents letters to the editor in response to the article "The Japanese Megaphone," by John B. Judis in the January 22, 1990 issue.

Several letters to the editor are presented in response to articles in previous issues including "A new push for public transportation," in the May 15, 1971 issue, "Where the boss gets an MBA on the job," in the May 8, 1971 issue, and "Picking up after Lockheed's mistakes," in the May 15, 1971 issue.

Presents letters to the editor referencing articles and topics discussed in previous issues. "Divided We Stand," which deals with liberalism; "Mel Gibson: Passionate Warrior," which focuses on the movie "The Passion of the Christ," directed Mel Gibson; "America's Gatekeeper," which discussed the proliferation of illegal immigrants in the U.S.