102 



production of O 2 in some way by the cucumbers themselves. 

 Whether this is a phenomenon of the metabolism of the species 

 or whether respiratory pigments of the nature of chlorophyll and 

 numerous others simply decompose CO 2 , is a question into 

 which we can not and do not have to enter. I could not 

 perform any experiments on this question myself, because 

 P ii 1 1 e r's work only came to my knowledge after my experimental 

 work had been completed. The latter assumption however has 

 its peculiar charms, especially when we remember that analo- 

 gous facts have been established for the starfishes. 



Putter's calculations are based on CO 2 production, CO 2 

 is one of the most important sources of C in his calculation 

 of the ,,Gesammtkohlenstoffausscheidung" and the total carbon 

 metabolism. On these figures his whole system of analysis of 

 the total metabolism" of Cucumaria is based. If this second 

 corner-stone of his building appears to be weakened, if in fact 

 the O 2 -production in the light is important enough to influence 

 the respiratory quotient in a measurable degree and the 

 above mentioned evidence seems to make this probable , the 

 whole system falls down and the conclusions are no longer 

 logical postulates. This is also true of his assumption of water- 

 soluble C- en N-compounds in the sea water as a source of 

 food. The work of Moore and his coworkers has shown this 

 very clearly. In the beginning of this chapter I had occasion 

 to call attention to one of Putter's serious methodical mistakes. 



But determinations even with these wrong methods are very 

 scarce in the work of Putter. Several facts are taken for 

 granted from the work of other authors. One of the most 

 striking examples is his assumption of the presence of a fatty 

 acid, dissolved in the sea water. Here he quotes Natterer who 

 in 1892 succeeded in destilling a ,,ganz geringe Menge" of a 

 substance, resembling palmitin or stearin by its smell when 

 heated, from 200 L. of sea water. Putter quotes this, but 

 does not try to repeat the experiment. 



From destillation experiments Putter concludes that 36 mgr. 

 of such acids are present in one Liter of sea water. But he 

 does not try to study the nature of this relatively enormous 

 quantity of acids more in detail. 



It is true that many circumstances make estimations of this 

 kind particulary hard, chiefly the presence of a large quantity 

 of chlorides and CO 2 which are normal constituents of the 

 sea water. Henze (Pfl tiger's Arch. f. d. ges. Physiol. Bd. 

 CXXIII. 1908. p. 487), however, using appropriate methods 

 taking a tube of metallic antimony and a glowing tube of lead 

 chromate and copper oxide to prevent hydrochloric acid or 

 other Cl-compounds from reaching the CO 2 apparatus, con- 

 cludes that the amount of organic material present, falls within 

 the limits of error* 



