worked closely with his father in his research work.
In 1918, Krebs, Sr., discovered an antibiotic mold which was successful in respiratory diseases. But, upon learning that the AMA did not like what he had done (it was 10 years before Alexander Fleming’s discovery of penicillin), he withdrew from membership in the AMA and never returned.
During the Prohibition in the 1920s, Krebs, Sr., accepted some business, analyzing whiskey smuggled on ships into San Francisco. The smug- glers were worried that it might contain wood al- cohol (isopropyl alcohol), which is deadly. So Krebs accepted the job of analyzing it, to be sure it was grain alcohol (ethyl alcohol).
This got him interested in what kind of en- zyme in the wooden barrels caused certain taste changes in the liquor. He found that mold on the barrel produced enzymes which affected the taste. Released into alcohol, they worked on the raw whiskey. The aging process took a long time, be- cause only a small amount of mold was released at a time.
Dr. Charles Gurchot, a pharmacologist who worked with Krebs, Sr., for years in the pursuit of the enzymatic control of cancer, later recalled, “This was the cataclysmic event. Dr. Krebs told me, ‘When I saw that enzyme doing all that digest- ing, it occurred to me it could be useful in cancer.’ ”
This idea—that some type of enzyme might be able to digest cancer cells—become some- thing of an obsession. In the early 1920s, Krebs, Sr., started searching for rats with cancers. Find- ing them, he would inject them with the enzyme and see what happened. Sometimes the tumor dis- appeared. Krebs, Sr., was sure he was on to some- thing.
But then his initial batch of enzymes ran out, and subsequent batches were not effective in elimi- nating tumors. So Krebs, Sr., made another cru- cial decision—which was a glorious mistake! He wanted to find a source of oak enzyme, and he thought to himself, “the oak belongs to the rose family, so I need to obtain the extract of a plant in that family.”
Now, the oak does not belong to the rose fam- ily; Krebs was a better chemist than botanist. But, just about that time, it turned out that the Washoe Indian girl who he had earlier adopted married a young, wealthy man from the Hawaiian Islands. They bought an apricot orchard, across the Bay in Oakland.
Now Krebs, Sr., had a source of a member of the rose family (apricots, peaches, almonds, etc., are in that family). —His error had led him to the richest source of amygdalin (laetrile) in the West- ern world. Yet, at this time, he knew nothing about
So Krebs, Sr., made an extract from the apri- cot kernels—and found it worked even better than ever in eliminating cancer in rats.
At that time, the process (which he greatly im- proved later) consisted of removing the oil from the seeds, grinding them up in water, filtering the mixture, precipitating the filtrate with alcohol, dry- ing the precipitate, redissolving it, then injecting it.
Krebs, Sr., was certain that he was extracting enzyme substances from the apricot pit. Among these substances, he tentatively identified emulsin, amygdalase, prunase, pectinase, and others. At the time, he thought emulsin was the active ingre- dient.
By this time, he was purchasing mice with spe- cially inbred tendencies to cancer. Most of the time, the mice were healed, but sometimes they sud- denly died. Krebs did not yet realize what was caus- ing the mice to suddenly die and how to solve the problem. It was not until later that, in solving this, he was able to better purify the extract.
In 1928 or 1929, Krebs gave the injections to humans—and found a consistent pattern of pain reduction and other good signs. But he kept try- ing to devise a way to produce a purer extract.
Gurchot later recalled that, of the first 25 or so patients, there were no toxic effects, other than occasional complaints of feeling chilly or “crawl- ing of ants” in the tumor area. In nearly all cases, the tumor either was reduced or completely dis- appeared.
At about the same time, several other physi- cians started working with him, and injecting the substance in their San Francisco area clinics.
Then one day, without telling Krebs, Sr., Gurchot prepared a batch of extract with all the enzymes killed. When Krebs, Sir., said it worked fine, Gurchot told him all the enzymes were dead. Immediately, Krebs knew that the presence of live enzymes was not a factor.
The team worked into the 1940s before they figured out the nature of the active ingredient.
At this point we will jump ahead to the late 1930s. By that time, there were several physicians throughout the world using Kreb’s method, includ- ing Dr. James Ewing, in New York City.
All the while, young Ernst Krebs, Jr., had been growing up, helping in the lab, cleaning up, and learning how to do research work. Obtaining a bachelor’s degree in bacteriology at the University of Illinois, he went on to obtain a master’s in phar- macology, and a doctorate in anatomy.
In 1938, young Krebs found John Beard’s