Livingston : Chemical stimulation of a green alga 25 



Literature 

 In any consideration of the general relation of the properties of 

 reagents to those of responding organisms, it is essential to have a 

 considerable mass of data from different forms of the latter. It is 

 also desirable, of course, to know the relative stimulating or toxic 

 power of as many elements as possible upon the same organism. 

 The literature contains a respectable number of titles dealing with 

 the question before us, but unfortunately the majority of the 

 determinations have been made in such a manner as to render 

 them quite inadequate for the present purpose. The work that 

 has been done on plants has been briefly summarized, up to the 

 time of his publication, by Copeland,* and a more recent review 

 of certain phases of the subject comes from the hand of Benecke.f 

 Observations which have an immediate relation to the results here 

 presented will be stated briefly in the following paragraphs. 



Acceleration of growth in Aspergillus and Penicillium was 

 studied by Richards, f and in part corroborated by Miss Watter- 

 son. § .For the former of these fungi ZnS0 4 accelerates growth 

 most at concentrations of 0.002 per cent. (6/// 100,000) to 0.004 

 per cent. (\2n\ 100,000). The salt is harmful at concentrations 

 from 0.05 per cent. (16;// 10,000) to 0.075 P er cent - (24/// 1,000). 

 FeS0 4 accelerates growth a little at 0.2 per cent. (26;// 1,000), and 

 the culture is normal at 0.033 P er cent - (44"/ 10 ' 000 )' CoS0 4 

 accelerates both fungi most at 0.002 per cent. (26/// 100,000), 

 while NiS0 4 shows the same response at 0.003 per cent. (85;// 

 100,000). I have translated the percentage figures approximately 

 into terms of a normal solution, and placed them in the paren- 

 thesis which follows each figure. 



Ono || worked with both algae and fungi. His results may be 



* Copeland, E. B. Chemical stimulation and the evolution of carbon dioxid. 

 Bot. Gaz. 35: 81-98, 160-183. 1903. 



f Benecke, W. Einige neuere Untersuchungen iiber den Einfluss von Mineral- 

 salzen auf Organismen. Bot. Zeitung 62 2 ; 113-126. 1904. 



I Richards, H. M. Die Beeinflussung des Wachsthums einiger Pilze durch chem- 

 ische Reize. Jahrb. Wiss. Bot. 30 : 665-679. 1897. 



§ Watterson, A. The effect of chemical irritation on the respiration of fungi. 

 Eull. Torrey Club 31 : 291-303. 1904. 



|| Ono, N. Ueber die Wachsthumsbeschleunigung einiger Algen und Pilze durch 

 chemische Reize. Jour. Coll. Sci. Imp. Univ. Tokyo 13 : 141-186. 1900. Also 

 Bot. Mag. Tokyo, 14: 75. 1900. 



