"A biochemist." Alcala tried to see past the meditative mask of the thin dark face. "He makes small job-lots of chemical compounds. Special bug spray for sale to experimental plantations, hormone spray for fruits, that sort of thing. Sometimes, when he collects some money ahead, he does research."
Camba waited, and his silence became a question. Alcala spoke reluctantly, anger rising in him. "Oh, it's genuine research. He has some patents and publications to his credit. You can confirm that if you choose." He was unable to keep the hostility out of his voice.
A waiter came and placed steaming platters of food on the table. Camba waited until he was gone. "You know him well, I presume. Is he sane?"
The question was another shock. Alcala thought carefully, for any man might be insane in secret. "Yes, so far as I know." He turned his attention to the steak, but first took three very large capsules from a bottle in his pocket.
"I would not expect that a doctor would need to take pills," Camba remarked with friendly mockery.
"I don't need them," Alcala explained. "Mixed silicones. I'm guinea pigging."
"Can't such things be left to the guinea pigs?" Camba asked, watching with revulsion as Alcala uncapped the second bottle and sprinkled a layer of gray powder over his steak.
"Guinea pigs have no assimilation of silicones; only man has that."
"Yes, of course. I should have remembered from your famous papers, The Need Of Trace Silicon In Human Diet and Silicon Deficiency Diseases."