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24O BOTANICAL GAZETTE. [ October. 



homogeneous body. It is a viscid fluid containing much 

 water, having parts easily motile, capable of swelling, and 

 possessing in a remarkable degree the properties of a colloid 

 It is a mixture of different organic matters, among which 

 albuminoids and members of the dextrine group are always 

 present. It has the consistence of a more or less thick mu- 

 cus, and is not miscible with water to any great extent 



From these accounts we see that the following points were 

 regarded as established: (1) All of the activities of the veg- 

 etable cell are manifested in its protoplasmic contents. (2 ) 

 Protoplasm consists chemically of a nitrogenous basis. (3) 

 Protoplasm has no demonstrable structure. (4) The proto- 

 plasmic contents in one vegetable cell are not connected with 

 the protoplasmic contents in adjoining cells. (5) The nucleus 

 and other vitalized granules in the vegetable cell are formed 

 by differentiation from amorphous protoplasm. 



It is now our duty to see in what manner these views have 

 been modified during the last twent\ , or rather ten, years. 

 In describing the changes of opinion, time will not suffice for 

 us to allude to most of the observers ; a few only can be 

 mentioned by name. 



The first thesis, namely, that all of the activities ol the 

 vegetable cell are manifested in its protoplasmic contents, 

 may be regarded as firmly established. It is at tbi 

 point in our present examination when, if we had time, 

 we should take up, one by one, the terms which have 

 been applied to some parts of what Mohl and Hofmeis- 

 ter knew as protoplasm. But we can only glance at them 

 in passing: Thus, cytoplasma is understood to be the mas 

 exclusive of the granular contents of all kinds : hyaloplasma 

 is the outer hyaline layer ; -polio-plasma is the grayish granu- 

 lar part. To these terms may be added others, such as far* 

 aplasma, etc. 



The second thesis, viz., protoplasm consists chemically 

 of a nitrogenous basis, remains unchanged. But, instead ot 

 regarding the protoplasmic basis as comparatively simple, 

 it is now known to be exceedingly complex, and to con- 

 tain numerous cognate proteids, some of which can be iden- 

 tified in the basic mass, others in the nucleus, and others still 

 in the vitalized granules. 



These researches must be considered also with reference 

 to those by two active investigators, Pfeffer and de Vries. 

 The former has shown the conditions under which active 

 protoplasm reacts in the presence of certain chemical ex- 



