394 Mr Gustav Mann on the 



A Comparative Study of Chlorophyll as occurring/ in some 

 Alyoi, Vascular Cryptoyams, and Phaneroyams. By 

 Gustav Mann. (With Spectra in Plate II.) 



(Read 10th April 1890.) 



After making myself familiar with the literature published 

 up to June 1889, 1 commenced studying the green colouring- 

 matter of the fresh-water alga Spiroyyra — firstly, as to its 

 microscopic appearance, and secondly, as to its absorption- 

 spectra, alike in the living organism and when extracted by 

 various media. I then examined spectroscopically the marine 

 alga Ulva, and finally I investigated representatives of the 

 vascular cryptogams and of the phanerogams. 



Structure of Chloroplasts in Spirogyra. 



As is well known, the chloroplasts occur in this alga in 

 the form of bands, arranged spirally in the peripheral proto- 

 plasm, and, according to the species, these vary in number 

 and in the amount of chlorophyll. Thus we find in Spiroyyra. 

 nitida, Dillw., considerably greener and less transparent bands 

 than in Spiroyyra juyalis, Dillw., and for this reason the 

 latter was chosen for the microscopic investigation of the 

 green ground-substance. I shall only state here the result 

 of my observations so far as they are necessary for the 

 understanding of the investigation of chlorophyll I record in 

 this paper. Other structural points are described in my 

 paper, " Some Observations on Spirogyra," which follows 

 this. 



The microscopic examination of Spiroyyra juyalis was 

 carried on with the help of a 1^ mm. Prazmowski water 

 immersion lens, in combination with various apochromatic 

 eye-pieces by Zeiss. 



The entire chlorophyll-band has a wavy outline, and is 

 bounded by a clear protoplasmic layer. This hyaline layer 

 does not give, however, the impression of a distinct mem- 

 brane, but resembles rather the clear protoplasmic material 

 lining the interior of a normal cell-wall. Enclosed by this 

 clear bounding layer is the ground-substance, which consists 



