346 THE AMERICAN MONTHLY [Oct. 



extinguish tuberculosis from his herd. In conclusion, I 

 wish to thank the veterinarians and all who have made 

 these studies possible. 



A Growing Cell. 



By A.RTHUR M. EDWAKDS, M. D., 

 NEWAKK, N. J. 



Hamilton L. Smith is the name of a person that all the 

 older microscopists were glad to have known and we who 

 were intimate with him must regret that the Societies and 

 Journals know him so seldom now. Diatoms were the 

 source of unmixed pleasure then and his magnificent col- 

 lection, containing that of de Brebisson also, often yielded 

 treasures to the anxious seekers after knowledge. It is 

 gone now into the hands of another who it is hoped will 

 contribute some of its beauties to the workl at large. Pro- 

 fessor Smith is busy with electricity he tells me and neg- 

 lects his microscope. Perhaps his growing slide has also 

 grown dusty and is out of use. 



But I was working then at living diatoms and have 

 been working at them till now for we are never too old to 

 learn and the problems of life still remain uncompleted. 

 I then made a growing slide of glass which I thought 

 was just as good as Smith's. At least it answered the 

 purpose and as it never has been described I wish to 

 describe it now. It was made for me by that ingenious 

 mechanic Greorge Wales, who is in New Jersey and mak- 

 ing camera lenses. 



But what I have got to say is about the growing cell. 

 The majority of microscopists at the time of which I am 

 speaking, that is about thirty years ago, were Diatomists, 

 that is to say they studied the shells of Bacillariacese to 

 see if they could by the use of the lenses then made bring 

 out the markings on Pleurosigma angulata, Amphipleura 

 pellucida and other fine-lined diatoms. They also worked 



