79' 



total quantity of perivisceral fluid of a starfish was secured. This 

 can easily be done by cutting off the tips of the arms and 

 allowing the „blood" to drip out. A cut in another arm facili- 

 tates this dripping out. 23 c.c. were secured. To this 5 c.c. of sea 

 water were added in which 350 mgr. of glucose had been 

 dissolved. The liquid was now put into a small Erlenmeyer 

 flask and shaken constantly by means of a hot-air automatic 

 shaker, in order to prevent the clotting of the corpuscles and 

 to mix the liquid thoroughly. From time to time a sample of 

 one c.c. was removed, as in the experiments mentioned above. 

 The corpuscles were centrifuged of and the sugar determination 

 made, as described above. 



The results of this experiment are given in table 13 and 

 plotted in fig. 7 (E). 



Table 13. 



Consumption of glucose (350 mgr.) by the corpuscles of 

 a starfish. 



These experiments have given us an opportunity, exceptional 

 from the general physiological standpoint, to study the disap- 

 pearance of food substances from the „blood" into the tissues. 

 One fact is very striking: that the consumption is not, or at 

 least not primarily, dependent on the quantity which is ojBFered. 

 In the 700 mgr. experiments we have after the lapse of a certain 

 time just as little left as when 75 mgr., less than one ninth 

 of the amount, is injected. There is no propoitionalitg between 

 quantity offered and consumption, the law of mass action can 

 therefore not be applied to the present case. The needs of 

 the tissue seem to be the factor of primary importance. 



They explain at the same time why the blood picture of the 

 invertebrates is so very inconstant, as I have already pointed 

 out in the chapter on the perivisceral fluid, when mentioning 

 the experiments of Dr. Morgulis. The concentration of the 

 products of hydrolytic cleavage of food substances and of waste 

 constituents depends largely or wholly on the feeding condition 

 of the moment. Constantly starving and having almost no reser- 

 ves as we will see in another chapter — , these animals 



live from day to day and have to fight for existence. 



