88 the president's address. 



useful instrument in the detection of crime and of criminals. In- 

 stances will occur to many of you of cases in which the microscope 

 has been applied to stains of blood, to fragments of hair, and in 

 other ways, with great success. A curious illustration of this will 

 be found in a suggestion made in France, during last year, in order 

 to prevent the forgery of bank-notes. There are some large toad- 

 stools, common everywhere in Europe, which are known by the 

 scientific name of Goprinus. These, as they grow old and decay, 

 melt into a black fluid of a permanent character, which has been 

 used as ink. Under the microscope this fluid consists of uniform 

 purple-black oval spores, which may be detected in the ink at any 

 time after its use. The proposal in the " Bulletin de la Societe 

 Botanique de France " was to the effect that bank-notes should be 

 printed or signed with this ink, which could always be verified 

 under the microscope. I believe the obstacle to this was that there 

 was no way known of manufacturing this coprin ink which forgers 

 themselves could not employ. 



2nd. The microscope may be useful in establishing innocence, as 

 well as detecting crime. I had the great pleasure, some years ago, 

 by means of the microscope, to save the reputation of an honest 

 man, and prevent his being dismissed from a situation in which he 

 had faithfully done his duty for many years. As, although I have 

 frequently mentioned the incident in conversation, it has, I believe, 

 never been published, I will record it here, as apropos to my sub- 

 ject. My deceased friend, Edward Blyth, the learned Indian 

 zoologist, one day brought me a few fibres of fine hair, with an 

 earnest request from a certain noble lord that I would, if possible, 

 ascertain to what animal they had belonged. He was under a strict 

 promise, he said, to give me no information, except that a matter of 

 grave importance rested on my answer. Of course, I carefully 

 examined the few fibres submitted to me, and was soon able to 

 decide that, beyond a doubt, they were the hair and wool of a hare. 

 I was enabled to arrive at this conclusion with the greater ease and 

 certainty that I had just previously been engaged with " the micro- 

 scope in its commercial relations," in minutely examining with a 

 view to comparing their structure with their relative felting proper- 

 ties, the various furs used by hatters, amongst which is hare's wool. 

 Poor Blyth was a very excitable man. When I told him my 

 decision he shook my hand, and the tears rushed to his eyes, as he 

 ejaculated " Thank God for that ! " And then he danced about the 



