J90 I 111-: mickos(()1m:. 



and ridges, and all the corpuscles were pinched and shrivelled, and 

 were much smaller than the fresh corpuscles, appearing as though 

 acted upon by an astringent. 



I took the trouble to measure seven of these corpuscles in a 

 given area of <^ne field of the microscope. They were as follows, 

 measured in both directions, and given in parts of an inch: 



(i) 1-6,000 1-4,500 



(2) 1-5,000 1-5,200 



(3) 1-4,500 1-3,700 



(4) 1-4,500 1-3,^*^71 



(5) 1-4,275 1-3,946 



(6) 1-6,000 1-3,461 



(7) '-3,461 1-4,687 



Here, also, I failed to get satisfactory evidence of the existence 

 of a net- work; though the shadows between the ridges and elevations 

 might resemble one. 



I carried my investigations to this point, and, after carefully 

 reviewing my work, to be sure I had made no mistake, I wrote to 

 Dr. Heitzmann again. I told him how I had proceeded and what I 

 had seen; I also enclosed some drawings of white corpuscles as they 

 appeared to me, and some of red corpuscles which had been acted 

 upon by the 40 per cent, solution of bichromate of potash, and asked 

 his interpretation. He sent me the following! letter: 



NEW YORK, Febr. 8, 1S80. 

 Dr. Lester Ccrtis: 



My Deat Doctor. — I have read your letter with great interest. It merely 

 proves how difficult it is to learn microscopy as an autodidact without the 

 assistance of a reliable teacher. The net-work is seen plainly when the 

 peripheral contour is not plain; in a globular body the central portion shows 

 the structure best when the periphery is out of focus. You evidently did not 

 learn to discriminate between different layers in one and the same corpuscle, 

 as illustrated try your sketches. You draw everything — in and out of focus. 

 You should draw only what is clear and sharp in one focus. Look at the 

 Histology Atlas by K. Klein and Noble Smith, first volume (1S79. Lippincott 

 publishers). E. Klein is the best microscopist of London, England; he draws 

 the net- work even nicer than it really appears, and gives me credit for the 

 discovery. 



Purchase for a few cents the recently issued Researches on red blood 

 corpuscles by L. Elsberg (1S79. Putnam Sons, N. Y., publishers) and you 

 will see and learn everything you desire. You evidently are a good faithful 

 man. Could not you come to New York in my laboratory? Here you would 

 learn more in one day than you possibly can learn home in months. 



Yours truly, 



Dr. C. Heitzmann. 



