2U 



THREE CRUISES OF THE " BLAKE. 



Fig. 137. — Velella mutica. 

 Vascular canal filled with yel- 

 low cells, magnified. 



glands, and Vogt regarded the yellow cells of Velella (Figs. 

 137, 137«) and Porpita as liver cells. 



In 1871 Cienkowsky expressed the 

 opinion that these yellow cells were para- 

 sitic alofae, basing- his view on the fact 

 that they survive the radiolarians, mul- 

 tiply, and become encysted, — pheno- 

 mena not in the least connected with 

 the life process of radiolarians. In 1879 

 Hertwio- discovered similar cells in acti- 

 niae which he considered as unicellular 

 alo-se. 



In 1881 Dr. Brandt confirmed Cien- 

 kowsky's discoveries, and strongly urged the para- 

 sitic nature of the cells. Geddes subsequently con- 

 firmed the views of Cienkowsky and Brandt, and 

 traced the presence of starch and of a cell wall 

 of true plant cellulose; he showed also that the 

 chemical composition and the mode of division of ^f' i-^J°— '"^"^- 



i ^ gle yellow cell, 



these yellow cells were those of unicellular algse, magnified. 

 for which he proposed the name of Philozoon. The exposure 

 of large quantities of radiolarians soon proved them to be stud- 

 ded with tiny gas globules, and a shoal of Velell^e yielded a 

 large quantity of gas containing more than twenty-one per cent 

 of oxygen. Dr. Geza Entz seems to have anticipated, as early 

 as 1876, the observations and theoretical deductions of both 

 Brandt and Geddes. 



In the relationship of these animals and plants, — for which 

 the name of Symhiosis, given by De Bary to an association of 

 dissimilar organisms, has been adopted, — it cannot be doubted 

 that the animal cell must be benefited by the death of the 

 vegetable cells which are digested, and that the animal cell is 

 constantly producing carbonic acid and nitrogenous waste, 

 which are of the first importance to the vegetable cell ; the 

 vegetable cell in its turn evolving oxygen under the action 

 of sunlight, which is taken up by the surrounding animal 

 tissues. 



This association, as far as we know, must be very beneficial, for 



