310 



The Structure of Colored Blood- Corpuscles. 



Fig. 7. 



Heitzmann demonstrated the exist- 

 ence of a net-work in amoebae, 

 blood-corpuscles of astacus and of 

 triton, human colorless blood-cor- 

 puscles and colustrum corpuscles ; 

 and, from direct observation of the 

 changes in the reticulum during 

 the contraction of the living body, 

 announced that the substance con- 

 stituting the net-work is itself the 

 living matter or bioplasson, i. e., 

 " the nucleolus, the nucleus, the granules with their threads, are 

 the living contractile matter proper." 1 Aside from some condi- 

 tions which do not here concern us, he described, and illus- 

 trated by the accompanying schema- 

 tic drawings, three states of the net- 

 work, viz.: that of rest (fig. 7), that 

 of contraction (fig. 8), and that of 

 extension (fig. 9). 



In the state of rest, the granules 

 or points of intersection of the 

 threads of the reticulum are in 

 equilibrium, and the meshes hold- 

 ing the lifeless '"protoplasmic fluid" 

 are uniformly distributed. In the 

 state of contraction, the granules increase in size at the expense 

 of the length of the uniting threads ; the granules approach 

 each other, and as the meshes between them become smaller, 



the fluid therein contained is forced 

 toward the part not subjected to 

 contraction. In the state of exten- 

 sion, the points of intersection de- 

 crease in size and move apart ; the 

 uniting threads become elongated, 

 while the lifeless fluid is forced into 

 the meshes from the contracting 

 portion. 



A fourth state of the living mat- 

 ter is assumed (hypothetically) by 



Fig. 8. 



Fig. 9. 



(1) Sitzb. d. Wien. Akad., vol. 67, div. 3, p. 110. 



