562 POPULAR SCIENCE MONTHLY. 



One of these men — Malpighi — was an Italian, and the other two 

 were Netherlands Dutchmen. Their great service "consisted chiefly in 

 this, that they broke away from the thraldom of book-learning, and, 

 relying alone upon their own eyes and their own judgment, won for 

 man that which had been quite lost, the blessing of independent and 

 unbiased observation." The importance of this step for its broad- 

 reaching effects even upon the intellectual life of our own time is not 

 easily overestimated. Much of the work of the present is built upon 

 the foundations they laid. 



There is a singularly unappreciative attitude towards scientific work, 

 of the biological kind, done before 1850, and a widespread disposition 

 to look upon the advances of the present time as peculiarly our own, 

 based wholly upon 'modern' work and 'modern' methods. This some- 

 times takes the extreme form, in the rising generation of practical 

 workers, of looking upon the scientific investigations of the past ten 

 years as of necessarily better quality than those of any preceding period, 

 because they are the most recent. But this is to do injustice to our 

 predecessors, and it is wholesome to take a look into the past, to see 

 some of the fine observational work done long ago, and to be com- 

 pelled to recognize the continuity of biological development, both as 

 regards work and ideas. 



If it were Johannes Midler with whom we were to deal, a marvel 

 could be shown, but the work of Malpighi. Swammerdam and Leeuwen- 

 hoek belongs to a period a century and a half before his time. For 

 these men it is just to claim, in addition to the service indicated above, 

 the possession of the true scientific spirit, the introduction of the micro- 

 scope and of more exact methods into scientific investigation, and, 

 through their work, the beginning of that better comprehension of the 

 natural universe that we call modern science. 



It is natural that working when they did, and independently as 

 they did, their work overlapped in many ways. Malpighi is noteworthy 

 for many discoveries in anatomical science, for his monograph on the 

 anatomy of the silkworm, for observations on the minute structure of 

 plants and on the development of the chick in the hen's egg. Together 

 with Grew, he is regarded as the founder of plant histology. Swammer- 

 dam did excellent and accurate work on the anatomy and metamorpho- 

 sis of insects and the internal structure of mollusks, frogs and other 

 animals. Leeuwenhoek is distinguished for much general microscopic 

 work; he discovered various microscopic animalcula; he established by 

 direct observation a connection between arteries and veins, and exam- 

 ined microscopically minerals, plants and animals. To him more than 

 to the others the general title of miicroscopist' might be applied. 



Let us, by taking them individually, look a little more closely at 

 the lives and labors of these men. 



