THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL. 



Vol. XVI. JANUARY, 1895. No. i. 



Microscopical Life in the Pliipps Conservatory Tanks, 



Allegheny. 



By JAMRS H. LOGAN, 



ALLEGHENY, PA. 

 WITH FRONTISPIECE. 



[Read by Dr. W. H. Holland for the author before the Iron City Micro- 

 scopical Society, Dec. 13, 1894.] 



The donor of Allegheny's greenhouse little thought 

 when establishing it how fine a treat was being provided 

 for those who delight in searching out the wonders of 

 microscopical life. In the large collection of plants, both 

 learned and unlearned may find much to admire and in- 

 struct. 



We are, however, now concerned with the tanks, 

 wherein exist an invisible flora and fauna equal in inter- 

 est and wonder to the larger ones which appeal to the 

 naked eye. Here, absence of violent agitation in the 

 water, together with abundant food and warmth, supply 

 the necessary conditions for the growth and develop- 

 ment of numerous animalcules and microscopic plants. 



There are three sources to which the presence of all 

 these forms may be referred. 



First, we have the river water which traversing the 

 mains and pipes carries along some of these organisms 

 or their eggs. Few and scattered though these be, they 

 increase prodigiously when placed amid favorable sur- 

 roundings. As most of these multiply by binary sub- 

 division, it is easy to see how in the course of not many 



