MICROSCOPIC FORMS IN FRESH WATER. 9 



were both large specimens of the cyclops. Was it because they 

 were large and consequently sluggish that they became in- 

 fested? And what was the parasite anyway? We have no book 

 here that mentions it at all. 



There seems also to be a remarkable dearth of books that give 

 anything like a connected account of the life history of these 

 small forms of life. This leaves, ot course, much to be desired, 

 but it also leaves a hiatus to be filled up by any energetic, am- 

 bitious, painstaking student. 



The manner in which these forms pass over our severe winters 

 is another subject for study, but if all is true that some authors 

 assert, the tenacity of life in some of them is remarkable, and I 

 would like here to quote from a German author a striking pas- 

 sage in that respect. After speaking of the vitality of seeds he 

 says : ''If then seeds that have been deprived entirely of air 

 for 16 years, through th*^ir own inherent vitality are enabled to 

 revive and flourish, so we shall also see that thoroughly dried 

 bodies of the simpler formed animals can also undergo such an 

 interruption of all visible vitality without injury. It seems to 

 be simply this, ihat thorough drying or cold holds in check 

 chemical atiiniiies that in the breathing animal tend to bodily 

 disinteg: ation. 



"This seems to be exemplitied by exi)eriment-5 lately tried by 

 the distinguished scientist, Raoul Pictet of (Jenf.. who caused 

 animals of different species to be frozen in blocks of ice, and 

 reduced the tetniicrature far below that of [Siberia, and yet when 

 they were thawed out they came to life again. Fish bore with- 

 out injury a temperature -S to 15 deg. (Centigrade), snakes 

 -25 to 28 deg., snails endured for a numl.ier of days a temperature 

 of -110 to 120 (leg. Frog's spawn, infusoria rotifers, etc.. resist- 

 ed for hours -60 deg. Microbes, baccilli and their spores were 

 apparently unchanged even for a length of time in a tempera- 

 ture of-200 deg. or even more when ^ilaced in liquid air. 



'"As all chemical change without exception ceases at -100 

 deg. (Centigrade), so must, in an animal or spawn that resists 

 for a lengih of time this tremendous reduction of temperature 



