It was just such a stick as the old-fashioned family practitioner used to carry--dignified, solid, and reassuring.

从句意角度看，本句应视为省略了主语和系动词：it was。这几个形容词都是说明修饰stick的。

类似表达比较常见：

Tom is a black boy --- honest, shy, and clever.

It was just such a stick as the old-fashioned family practitioner used to carry--dignified, solid, and reassuring.

dignified, solid, and reassuring 都是前面名词stick修饰成分。

网友的句子来自下面这段文章：

Hound of Baskervilles Chapter 1 Mr. Sherlock Holmes Mr. Sherlock Holmes, who was usually very late in the mornings, save upon those not infrequent occasions when he was up all night, was seated at the breakfast table. I stood upon the hearth-rug and picked up the stick which our visitor had left behind him the night before. It was a fine, thick piece of wood, bulbous-headed, of the sort which is known as a "Penang law- yer." Just under the head was a broad silver band nearly an inch across. "To James Mortimer, M.R.C.S., from his friends of the C.C.H.," was engraved upon it, with the date "1884." It was just such a stick as the old-fashioned family practitioner used to carry -- dignified, solid, and reassuring. "Well, Watson, what do you make of it?" Holmes was sitting with his back to me, and I had given him no sign of my occupation. "How did you know what I was doing? I believe you have eyes in the back of your head." "I have, at least, a well-polished, silver-plated coffee-pot in front of me," said he. "But, tell me, Watson, what do you make of our visitor's stick? Since we have been so unfortunate as to miss him and have no notion of his errand, this accidental souvenir becomes of importance. Let me hear you reconstruct the man by an examination of it." "I think," said I, following as far as I could the methods of my companion, "that Dr. Mortimer is a successful, elderly medical man, well-esteemed since those who know him give him this mark of their appreciation." "Good!" said Holmes. "Excellent!" "I think also that the probability is in favour of his being a country practitioner who does a great deal of his visiting on foot." "Why so?" "Because this stick, though originally a very handsome one has been so knocked about that I can hardly imagine a town practitioner carrying it. The thick-iron ferrule is worn down, so it is evident that he has done a great amount of walking with it." "Perfectly sound!" s