首先他一下就看出了华生是有医学气质的人，再加上军人的感觉，自然就是一个军医了。

　　2. for his face is dark, and that is not the natural tint of his skin, for his wrists are fair,

　　→He has just come from the tropics.

　　接下来，华生脸这么黑，而手腕却是比较白皙的肤色，所以肯定是在热带地区晒黑的。

　　3. as his haggard face says clearly,

　　→He has undergone hardship and sickness.

　　再然后，面容如此憔悴，肯定是经历过比较严重的疾病

　　4. He holds it in a stiff and unnatural manner,

　　→His left arm has been injured.

　　从华生僵硬且不自然地扶着他的左臂来看，肯定左臂受过伤。

　　5. Where in the tropics could an English army doctor have seen much hardship and got his arm wounded?

　　→Clearly in Afghanistan.

　　那么一个英国军医在热带的什么地方才会遭受如此痛苦和伤病，那肯定是阿富汗了。

　　最后福尔摩斯就直接跳过过程直接说出了结果，自然也就惊到了我们天真烂漫的华生医生。这样的一个段落，柯南·道尔笔下的福尔摩斯描述的一气呵成，而对于我们学生读者来说，这样的文字，对于我们的意义有二。

　　第一，很多生词以文本为基础，成组的出现在我们面前，方便我们记忆。对于一个华生一样的人物，他是：

　　medical type with the air of military; tint and haggard face and fair wrists; stiff and unnatural manner; injured=wounded.

　　*fair这个词可以表示一般的，比如在TOEFL的分数报告中，写作部分分成了三个级别，good-fair-limited; 而在形容人的时候，他又有皮肤白皙的;头发金黄色的意思。

　　第二，由于逻辑关系一环扣一环，很有可能一遍并不能完全明白所有福尔摩斯的推理。这时建议大家一定不要认为自己基本懂了就跳过，而是要再次确认每一个推理的细节，以及很多因果逻辑关系，最后总结出福尔摩斯所有的推理过程。

       还有一个推理过程是出现在血字研究(A Study in Scarlet)这篇的结尾，福尔摩斯在华生和雷斯垂德警官面前直接抓住杰弗逊·霍普这个真凶，留下众人完全不知所措。后来案子结束了，回到贝克街221B福尔摩斯给华生医生解释了他推理的过程。

　　“I had already determined in my own mind that the man who had walked into the house with Drebber was none other than the man who had driven the cab. The marks in the road showed me that the horse had wandered on in a way which would have been impossible had there been anyone in charge of it. Where, then, could the driver be, unless he were inside the house? Again, it is absurd to suppose that any sane man would carry out a deliberate crime under the very eyes, as it were, of a third person, who was sure to betray him. Lastly, supposing one man wished to dog another through London, what better means could he adopt than to turn cabdriver? All these considerations led me to the irresistible conclusion that Jefferson Hope was to be found among the jarveys of the Metropolis”

　　这是其中一个段落，也是最精彩的一段。

　　1. 首先通过道路上的印记，他确认肯定是有人在控制这匹马的，那么马车的车夫肯定是和被害者Drebber一同走进了案发地点的房子。

　　2. 接下来，很难想象会有一个人在有第三个人存在的情况下犯下这个案子，所以凶手就是这个马车夫无疑。

　　3. 最后，当一个人在追踪他的仇人的时候，做马车夫应该是最好的选择了。所以福尔摩斯确认要从伦敦的马车夫中寻找这个叫杰弗逊霍普的犯人，当然这就是非常简单的工作了。