THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



Vol. IX, No. 15.] SEPTEMBER, 1915. [ v 1 ho x ?x s no e ! 5 



The Influence of Light on Reproduction 



in Vorticella. 



IDA H. HYDE AND CHRISTINE SPREIER. 

 From the Physiological Laboratory of the University of Kansas. 



THE aim of the work briefly described in this article has 

 been to ascertain the influence of monochromatic and 

 different intensities of light on the reproduction of vorticella. 



The vorticella were transferred by means of a Barber* capil- 

 lary pipette, held in a modified triple-movement pipette holder. 



From a culture of the unicellular organisms, that had been 

 kept covered in the dark for several months, many encysted 

 zooids were isolated and transferred to a culture media, con- 

 sisting of an infusion of Timothy hay. The infusion had been 

 filtered, sterilized by boiling, and kept in sterilized sealed tubes 

 until needed. 



The encysted forms were under observation in a hanging 

 drop placed in an open-end moist chamber. 



As soon as the zooids emerged from their cysts they were 

 removed to a drop of the sterilized infusion placed on a Hemo- 

 cytometer micrometer slide. By this means the direct in- 

 crease in organisms could be ascertained. The slides with the 

 young zooids were placed in a Petri dish that contained a thin 

 layer of water to prevent rapid evaporation of the solution. 

 The organisms of the same age thus secured were kept for 



Received for publication January 15, 1915. 



* Barber, M. A., Jour, of Infections Dis., 1911, vol. VIII, p. 348. 



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2 — Univ. Sci. Bull., Vol. IX, No. 15. 



