392 PEOFESSOR ARTHUR BOETTCHER. 



shape are, however, not entirely absent in the red blood-cor- 

 puscles. As is well known, the disk shape of the mammalian 

 blood-corpuscle can change into the mulberry or spherical form, 

 and the mulberry -shaped blood-corpuscles can also become 

 spherical. The dift'erences in form occurring in the elUptical 

 blood-coi'puscles are much less. Those of the camel appeared to 

 me especially unchangeable. Somewhat more varied is the form 

 of the frog's blood-corpuscles. But all varieties observed in the 

 red blood-corpuscle, and also in the disk-shaped blood-corpuscles 

 of mammalia, remain for a considerable time unchanged. The 

 individual blood-corpuscles are always motionless, and the 

 tranformations which take place in them during long periods of 

 time cannot therefore be compared to the phenomena of con- 

 tractility observed in the colourless blood-corpuscles. 



If, however, as I have endeavoured to show for the red blood- 

 corpuscles of man and of the frog, the protoplasm occurs in such 

 exceedingly varied form, and with such peculiar arrangement as 

 is usually only seen in protoplasm undergoing active movement, 

 one appears justified in questioning whether it does not retain 

 its mobility within the non-contractile homogeneous cortex. 

 Unfortunately the circumstances are so unfavorable that it would 

 be almost impossible to establish by direct observation any 

 movements iu the protoplasm of the red blood-corpuscles. This 

 does not, however, preclude the possibility of the protoplasm 

 within the homogeneous case of hsemoglobin being in a state of 

 continuous movement. Eor it is only in living protoplasm that 

 we are acquainted with such filamentous processes, such discs 

 and such net-like arrangements, and again with such globular 

 accumulations as we have met with in the colourless substance 

 of the red blood-corpuscles. The fact that the object presents 

 such inseparable difficulties, that it is impossible to decide by 

 direct observation whether iu the interior of the red blood- 

 corpuscles a movement takes place or not, does not give us any 

 right to deny it. On the other hand, many of the peculiar 

 forms, which I have described in the human blood- corpuscles 

 treated by corrosive sublimate, appear to me to be best ex- 

 plained by supposing that the homogeneous cortex often takes a 

 passive part in the movements of the protoplasm. I would class 

 the hsemoglobin-envelope of the red blood-corpuscles with the 

 capsule of cartilage cells, and with the cellulose membrane of 

 vegetable cells, in so far as these are to be regarded as trans- 

 formed protoplasm, since, for reasons which I have stated else- 

 where, I must consider the cortical layer as the result of a 

 process of develo[)inent which deprives the blood-cells more and 

 more of their protoplasm, and finally converts them into homo- 

 geneous bodies. • DoRPAT, January, 1877. 



