Editor: Reading the ''Waste on Sludge'' letter to the editor (Jan. 18), I knew that Robert Oler of Towson, who commented on the Back River treatment plant, did not live in the Essex-Dundalk area.
I can understand Mr. Oler's concern with cost, competitive bidding and air pollutants are valid. If this treatment plant were nestled in the Towson area I'm sure the people who live there would go to greater lengths and tax money to rectify this $H problem. But the treatment plant is in the Essex-Dundalk area and not in Towson. The communities that surround this treatment plant have a much more valid reason for concern.
Editor: Patrick Stone's Nov. 30, 1991 reply to Moise H. Goldstein Jr.'s letter (Oct. 28) contains a stunning error: ''Absolutely no scientific evidence exists to support" Dr. Goldstein's claim regarding children's achievements who are exposed to signed languages from birth as compared with children's achievements who are exposed to spoken languages.
In my Science magazine article (March 22, 1991), I report that deaf children exposed to sign languages from birth achieve each and every linguistic milestone on the identical time table as hearing children exposed to spoken languages from birth. I also cite research in progress in which the same holds true for hearing children born in bilingual homes; one parent signs and one parent speaks.
That is, even children who are exposed to both signed and spoken languages from birth do not ''prefer'' speech. Instead, they acquire both signed and spoken languages on the identical time course, reaching all linguistic milestones (e.g., vocal and manual babbling, first words and first signs, first grammatical combinations of signs and words, respectively, etc.) at the same time.
One would think that if speech were ''better'' or ''special,'' and/or if speech were more suited to the human brain's maturational needs in development, this very group of children would attempt to glean every morsel of speech that they could get from their environment -- perhaps even turning away from the signed input, favoring instead the speech input. But this is not what happens. Signed and spoken languages are acquired effortlessly by these children, and all of the children, including the deaf children of deaf parents, acquired signed languages in the same way, at the same time, exhibiting the identical linguistic, semantic, and conceptual complexity (stage for stage) hearing children acquiring spoken languages.
I'm afraid that the human brain does not discriminate between signed versus spoken languages -- people do.
Laura Ann Petitto.
The writer is associate professor of psychology, McGill University.
Editor: Watching the recent appearance of Lee Iacocca and other auto leaders in Asia, I started to think that what they represent is not leadership, but a style of management that is outdated.
Mr. Iacocca seems to think that if he blusters and bullies, he will get his way -- never mind the merits of what he says. The auto industry might be better served to get new leadership: more flexible, less overpaid, and able to listen and learn from others.
Laura J. Platter.
Editor: It's true. Helmets do not prevent accidents. But I don't recall anyone who supports a mandatory helmet law ever suggesting that the intent of the law is accident prevention.
As an occupational therapy student at Towson State University, I am learning rehabilitation techniques as part of my course work. From my viewpoint, the intent of a mandatory helmet law is reduction of head injury when accidents occur.
The fact that accident fatalities per 10,000 motorcycle registrations have decreased by 15 percent could be misleading in terms of health care costs.
Perhaps more head injury victims not wearing helmets are being kept alive by new technology and advanced trauma care methods. But what about costs and quality of life issues?
Nancy Papa Doran.
Editor: Richard Vatz and Lee Weinberg must be mellowing. In their recent Opinion * Commentary piece, ''Insuring the Mentally Ill,'' they deign to acknowledge that schizophrenia and ''possibly 'bipolar disorders' such as manic-depression'' are medical problems. They even note that their guru, Thomas Szasz, now concedes schizophrenia's biological cause.
When such ardent disciples of the mental health flat-earth-society as these begin to place facts above ideology, there's hope for us all -- especially for people fighting not only the pain and disability of mental illness but ignorance as well.
Herbert S. Cromwell.
The writer is executive director of the Maryland Association of Psychiatric Support Services Inc.
Fed Up with Excesses
Editor: Most of the tax burden of this nation is borne by the middle class.
Our country's huge and uncontrolled deficits continue to mount each year because we are spending far beyond our means.