The differences in memory which men exhibit are not, among their other human qualities, the least. As is well known, this difference is expressed not only in the vigor, reliability, and promptness of their memory, but also in the field of memory, in the accompaniment of rapid prehensivity by rapid forgetfulness, or slow prehensivity and slow forgetfulness, or in the contrast between narrow, but intense memory, and broad but approximate memory. Certain special considerations arise with regard to the field of greatest memory. As a rule, it may be presupposed that a memory which has developed with especial vigor in one direction has generally done this at the cost of memory in another direction. Thus, as a rule, memory for numbers and memory for names exclude each other. My father had so bad a memory for names that very frequently he could not quickly recall my Christian name, and I was his own son. Frequently he had to repeat the names of his four brothers until he hit upon mine, and that was not always a successful way.[223] When he undertook an introduction it was always: “My honored m--m--m,”--“The dear friend of my youth m--m--m.” On the other hand, his memory for figures was astounding. He noted and remembered not only figures that interested him for one reason or another, but also those that had not the slightest connection with him, and that he had read merely by accident. He could recall instantaneously the population of countries and cities, and I remember that once, in the course of an accidental conversation, he mentioned the production of beetroot in a certain country for the last ten years, or the factory number of my watch that he had given me fifteen years before and had never since held in his hand. He often said that the figures he carried in his head troubled him. In this regard the symptom may be mentioned that he was not a good mathematician, but so exceptional a card player that nobody wanted to play with him. He noticed every single card dealt and could immediately calculate what cards each player had, and was able to say at the beginning of the game how many points each must have. Such various developments are numerous and of importance for us because we frequently are unwilling to believe the witness testifying in a certain field for the reason that his memory in another field had shown itself to be unreliable. Schubert and Drobisch cite examples of this sort of thing, but the observations of moderns, like Charcot and Binet, concerning certain lightning calculators (Inaudi, Diamandi, etc.), confirm the fact that the memory for figures is developed at the expense of other matters. Linné tells that Lapps, who otherwise note nothing whatever, are able to recognize individually each one of their numberless reindeer. Again, the Dutch friend of flowers, Voorhelm, had a memory only for tulips, but this was so great that he could recognize twelve hundred species of tulips merely from the dry bulbs.