14 INTRODUCTION. 



becomes so disheartened since everything is so new and strange, and 

 there seems to be no one within call to lead him out of the difficult- 

 ies, or out of the embarrassment of scientific riches, that he is entirely 

 discouraged, his enthusiasm is lost, and with this loss is abandoned 

 a study that would have lessened his cares, increased his joy in living 

 and lengthened his life. The beginner working alone wastes much 

 time. To be sure, he may before long learn that a green object that 

 stands still is a plant, or may be; and also before long he hears that 

 all green microscopic objects that stand still are not always plants. 

 If he have a teacher his condition is a more favorable one; but if he 

 be alone he must have an artificial guide, or fail. For such students 

 the artificial keys are providential. Once introduced to them he is 

 ready to go on to new conquests. The use of such tables in the 

 popular treatises on botany has done more to popularize that beautiful 

 study than a score of learned monographs on the subject. As soon 

 as the pupil learns that he can by his own efforts obtain even the bo- 

 tanical name of his plant, a feeling of enthusiasm fills his heart, and he 

 is eager for another specimen to analyse. And in the analysis he is 

 learning the principles of classification, the structure of the specimen 

 and the function of the various organs. By means of the key he goes 

 with little trouble and waste of time to the order, there he finds 

 another key that leads him pleasantly to the genus, and perhaps a 

 third that takes him to the species. There he finds the plant exactly 

 described. He has had the prominent characters brought to his no- 

 tice in a pleasing way, and the final result is that he not only learns to 

 love the science of botany, but that he soon learns to know at a 

 glance, without the use of the artificial key, to what order a strange 

 specimen may belong. He has become scientific without knowing 

 how he became so. He has travelled by the royal road. It is so, or 

 should be so, in the science of microscopy, to call for convenience a 

 science that which is really a combination of all the sciences. 



If every department of microscopy could have an artificial key to 

 open the doors of its treasure-houses, the amateur would have a hap- 

 pier time, science would be benefitted and the maker of the key, the 

 scientific artisan, would himself be blessed both in this world and in 

 the next. Such a pleasing state of affairs can not be attained. The 

 doors are too numerous to be opened by a single key. To make the 

 proper number is not possible for one worker, however willing he may 

 be to try. Each specialist could forge a key to the doors or to the 

 dark passage-ways of his special scientific castle, and offer it to those 

 that would follow after him if they could. But the specialists are not 



