PROGRESS IN ANATOMY AND PHYSIOLOGY 



ence may be said to date from this period. Hitherto, 

 ever since the discovery of magnify ing -glasses, there 

 had been here and there a man, such as Leuwenhoek or 

 Malpighi, gifted with exceptional vision, and perhaps 

 unusually happy in his conjectures, who made important 

 contributions to the knowledge of the minute structure 

 of organic tissues ; but now of a sudden it became pos- 

 sible for the veriest tyro to confirm or refute the la- 

 borious observations of these pioneers, while the skilled 

 observer could step easily beyond the barriers of vision 

 hitherto quite impassable. And so, naturally enough, 

 the physiologists of the fourth decade of our century 

 rushed as eagerly into the new realm of the microscope 

 as, for example, their successors of to-day are exploring 

 the realm of the X ray. 



Lister himself, who had become an eager interrogator 

 of the instrument he had perfected, made many impor- 

 tant discoveries, the most notable being his final set- 

 tlement of the long -mooted question as to the true 

 form of the red corpuscles of the human blood. In 

 reality, as everybody knows nowadays, these are bicon- 

 cave disks, but owing to their peculiar figure it is easily 

 possible to misinterpret the appearances they present 

 when seen through a poor lens, and though Dr. Thomas 

 Young and various other observers had come very near 

 the truth regarding them, unanimity of opinion was pos- 

 sible only after the verdict of the perfected microscope 

 was given. 



These blood corpuscles are so infinitesimal in size that 

 something like five millions of them are found in each 

 cubic millimetre of the blood, yet they are isolated par- 

 ticles, each having, so to speak, its own personality. 

 This, of course, had been known to microscopists since 



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