Chapter 17, for the first time in the novel, is devoted solely to Doc. 

Although he is constantly surrounded by people, Doc usually prefers to be alone. Mack may be the only one who notices the scientist is a "lonely and set-apart" man, but it is true. Even on the frequent occasions when Doc has a woman in his laboratory, he appears, to Mack at least, to be lonely. 

Although Doc occasionally takes someone on his collecting expeditions, most of the time, he spends his time alone, crawling over boulders and turning over rocks. Doc has been a marine biologist for a long time. He knows not only when the tides come in and go out but also when certain tides are likely to provide the greatest bounty. When one of these special tides is scheduled to arrive, Doc prepares his tools and packs up his truck with bottles and preservatives and heads out. 

On this trip, he has an order for small octopi, and one of those special tides is due to come in. Unfortunately, he will have to travel a good distance to get to it, to a beach some five hundred miles away. He has to time his travel carefully in order to arrive when the tides retreat. 

The low tide is scheduled for Thursday morning, so Doc has to leave Cannery Row early on Wednesday. He could have used a companion to help collect, but this time no one is available to make the trip with him. Mack and the boys are away collecting frogs for him; the women he knows have to work. Doc even asks Henri, the eccentric painter and builder of non-seagoing boats, but Henri has become enthralled by a local store that has hired a flagpole skater to attract attention. He does not want to miss a minute of the action. 

So Wednesday morning, Doc sets out solo for La Jolla's intertidal range. To many people, an entire day and night might seem like a long while for the distance that needs to be covered, but Doc likes to take his time. He drives slowly and stops frequently for burgers. At one of the diners on a past trip, someone quipped that Doc loved beer so much he probably would even drink a beer milkshake. For some reason, the idea stuck with Doc. Every time he saw a milkshake machine after that remark, he wondered about it. 

He knows, however, that just being curious is not enough reason for people to let him try one. He thinks about how many lies he has to tell because he enjoys wearing a beard. "People were not liked for telling the truth," he concludes. But tell anyone who asks that the beard covers a scar, and they are satisfied. It is harder to come up with an acceptable reason to want a beer milkshake. 

After driving for some time, Doc spots a hitchhiker. He does not always pick them up but he wants some company. Sometimes a hitchhiker is a bad companion, but he could always be dropped off soon if told that the trip will be a short one. If it turns out that the rider is a good conversationalist, as sometimes happens, then it works out for both driver and rider. 

This time, Doc does not choose very well. The man gets into the truck, but then, seeing Doc with a beer in his hand, immediately begins lecturing him about drunk driving. The rider tells Doc he could threaten his own life if he wanted to, but had no business endangering his as...