OSMOTIC PRESSURE. 33 



tain more than an equal volume of serum. These bodies are equally 

 absorbed by the blood corpuscles. 



OVERTON had previously arrived at the same results, using plant 

 cells, but urea is probably more quickly taken up by the blood corpuscles 

 than by plant cells, and ammonium salts also seem to pass more easily 

 into the blood corpuscles than into the plant cells. 



In regard to other salts HEDIN'S results have been substantiated 

 by OKER-BLOM, 1 by estimating the electrical conductivity. 



It must also be stated that according to HEDIN, only those bodies 

 which do not pass, or pass only slowly into the cells, can essentially alter 

 the volume of the cells. A close correspondence exists in this regard 

 between the plant and animal cells. 



GiJRBER found that when blood corpuscles are repeatedly 

 washed with salt solution until the wash solution does not show 

 any alkaline reaction, and are then ^suspended in NaCl solution 

 and treated with C02, the alkaline reaction increased while the 

 blood corpuscles became richer in chlorine. No exchange of K or Na 

 took place. 2 GURBER explains the experiment as follows: the carbonic 

 acid set a small amount of HC1 free from the salt, and this HC1 was taken 

 up by the blood corpuscles. The Na2CO 3 formed at the same time 

 gave the alkaline reaction to the solution. KOEPPE 3 as well as HAM- 

 BURGER and v. LIER 4 claim on the contrary that an exchange of HCOs- 

 ions and Cl-ions takes place between t'he blood corpuscles and the solu- 

 tion, and HAMBURGER and v. LIER claim to have shown that the blood 

 corpuscles are permeable only for anions, while the cations do not pass 

 in. GURBER'S explanation is simpler and stands in accord with the 

 facts as found. The theory as to the permeability for anions does not 

 explain the fact that the anions in the blood corpuscles are so different 

 from those in the plasma. 



Muscle Experiments. By investigations on the changes in the 

 weight (instead of the volume changes in the above-mentioned exper- 

 iments with plant cells and blood corpuscles) which frog muscles undergo 

 in solutions, various experimenters, NASSE, S LOEB, G and OVERTON, ? have 

 tried to prove the ability of muscle to take up various substances. OVER- 

 TON found that as long as the irritability of the muscle was retained 

 the muscle took up the same bodies as the plant cells. The sarcolemma 



1 Pfluger's Arch., 81, 167, 1900. 



2 Sitzungsber. d. med. phys. Gesellsch. zu Wiirzburg, 1895. 



3 Pfluger's Arch., 67, 189, 1897. 



4 Arch. f. (Anat. u.) Physiol., 1902, 492. 



5 Pfluger's Arch., 2, 114, 1869. 



6 Ibid., 69, 1; 71, 457, 1898. 



7 Ibid., 92, 115, 1902; 105, 176, 1904. 



