DEVELOPMENT OF LIVING MATTEE. 47 



either scattered through the body of the amoeba, or accumulated 

 in groups, but little exceeding in size that of the nucleus. Both 

 kinds of granules are connected, by means of delicate filaments, 

 with the reticulum of the living matter of the lump. The pale 

 gray nuclei of such older amoebee always exhibit vacuoles. 



If we add a drop of glycerine, diluted with one-half water, to 

 a specimen containing amoebae of early formation, each amoeba 

 will, the moment it is reached by the glycerine, suddenly contract 

 into a homogeneous, yellowish, very shining lump, the size of 

 which is only a small fraction of its former circumference, or the 

 amoeba shrivels to a scolloped lump, which by the bursting of 

 peripheral vacuoles becomes in a few seconds nearly homo- 

 geneous. Such lumps remain, as a rule, unchanged. 



Amoebae of a later period do not react uniformly to glycerine. 

 If both a finely and coarsely granular amoeba should be present 

 in the field of vision, the latter, on addition of glycerine, will 

 rapidly be transformed into a homogeneous lump, while the 

 former will slowly shrivel, sometimes only become corrugated 

 on its surface, and retain its finely granular character, becom- 

 ing, however, motionless and globular. Most of the lumps, 

 sprung from coarsely granular amoebae, enter the globular con- 

 dition slowly. Some even remain unchanged. Whether this 

 difference is due to difference of concentration of the glycerine 

 which reaches different amoebae, even in one field of vision, I 

 am unable to decide. 



By draining off the glycerine and replacing it with water, 

 all lumps are gradually transformed into globules, but none of 

 them recover mobility. 



The series of changes which the coarse granules of the blood- 

 corpuscles of craw-fish undergo, without the addition of any re- 

 agent, are described in Chapter II., page 23. An originally 

 solid, homogeneous lump of living matter, in a short time, 

 under our very eyes, becomes at first vacuoled, and at length 

 transformed into a delicate reticulum. 



Cartilage-corpuscles. In comparing the corpuscles of cartilage 

 of mammals (I have examined the cartilage of the knee-joints of 

 dogs, cats, and rabbits) of different age, marked differences are 

 observed, dependent on the age of the animal. 



The cartilage cavities of a pup, five days old, hold proto- 

 plasmic bodies, the nuclei of which are homogeneous, yellowish, 

 and very shining, and sometimes contain vacuoles. Besides, 

 there are numerous smaller cavities entirely filled with a mass, 



