1898.] MICROSCOPICAL JOURNAL 163 



his clinic. For five years he has labored there trying to 

 discover in the sputum of whooping cough patients the 

 elusive bacillus. Though it was found in each case, its 

 cultivation until recently was a failure. Finally, the 

 desired result was obtained by planting the sputum on 

 human blood serum. A tiny particle of the sputum, 

 under the proper treatment will reveal bacilli by the 

 thousand. 



The Fresh water Hydra. — My friends, it is true, laugh 

 at me, and I laugh at them. They wonder why I am so 

 devoted to "a glass globe full of water, with a few plants 

 and snails," and I tell them that while they see much to 

 admire in horticulture, agriculture, and a host of other 

 "cultures," I am an enthusiast about hydra-culture. 

 Indeed, in this small and insignificant aquarium I have a 

 flock of fresh-water polyps, called "hydras," full of 

 interest, full of wonder. I envy Trembley, who in 1744 

 published A Memoir on the Fresh-water Polyp, the intense 

 pleasure he felt in unraveling the life history of these 

 creatures. He was investigating the unknown when he 

 studied the strange phenomena connected with them, and 

 was transported with astonishment. I know, from the 

 labors of others, what to expect, and yet T am lost in 

 wonder. 



We may be thankful that these animals are so small as 

 they are; for, if they were only a few feet in length, we 

 should have in our water world many a repetition of the 

 devastation said to have been caused by the Lerna^an 

 Hydra, whose destruction was one of the gigantic labors 

 of the hero Hercules. As it is, the longest you can find is 

 only an inch in length. They can, however, be easily seen 

 with the unaided eye, and with the help of a pocket lens 

 can to some extent be studied. In fact, Trembley, the 

 famous observer of them, had nothing better. It is only 

 when we wish to examine minute details that the use of the 

 elaborate microscope is called for. A group of them at- 

 tached to the rootlets of duckweed or the under side of the 

 leaves or on the stems of plants is a curious sight. 



