PROTOPLASM OF THE LIVING CELL 



537 



the group of thallophytes, we find among the lower types of that 

 group a yet simpler mode of bringing it about ; for there is strong 

 reason to regard the act of ' conjugation ' which takes place in 

 the Conjugate and in some fungi in the same light, and to look 

 upon the ' zygospore,' l which is its immediate product, as the 

 originator (like the fertilised embryo-cell of the phanerogamic seed) 

 of a ' new generation.' 

 Great attention 

 has recently been 

 paid by Strasburger 

 and others to the con- 

 stitution of the endo- 

 plasm and to the 

 processes connected 

 with cell-division. On 

 both these subjects it 

 is impossible here to 

 give more than the 

 barest outlines. Stras- 

 burger distinguishes 



between the following p IG< 414. Successive stages of free-cell formation 

 differentiated parts of in embryo-sac of seed of scarlet-runner; a, a, a, 

 the protoplasm of the completed cells, each having its proper cell-wall, 

 i- r ,, , nucleus, and endoplasm, lying in a protoplasmic 



living cell I - J.ne mass, through which are dispersed nuclei and cells 

 protoplasm outside the in various stages of development. 



nucleus he terms the 



cytoplasm ; the portion which constitutes the nucleus is the 

 n acleoplasm ; that which enters into the composition of the 

 chlorophyll corpuscles and other allied substances is the chromato- 

 plasm. Each of these three portions of protoplasm is composed of a 

 hyaline matrix or hyaloplasm and of imbedded granular structures 

 or microsomes. A distinct substance, known as nuclein, absent from 

 the cytoplasm, appears to enter into the composition of the nucleus. 

 The various substances imbedded in the cytoplasm are known under 

 the general name of plastids. If colourless, they are leucoplasts, and 



1 The term ' spore ' has been long used by cryptogamists to designate the minute 

 reproductive particles (such as those set free from the ' fructification ' of ferns, mosses, 

 &c.) which were supposed in the absence of all knowledge of their sexual relations 

 to be the equivalents of the seeds of flowering plants. But it is now known that such 

 ' spores ' have (so to speak) very different values in different cases, being, in by far the 

 larger proportion of cryptogams, but the remote descendants of the fertilised cell which 

 is the immediate product of the sexual act under any of its forms. This cell, which 

 will be distinguished throughout the present treatise as the oosphere, is the real repre- 

 sentative of the ' germinal cell ' of the ' embryo ' developed within the seed of the 

 flowering plant. On the other hand, the various kinds of non-sexual spores emitted 

 by cryptogams, which have received a great variety of designations, are all to be 

 regarded (as will be presently explained) as equivalents of the leaf-buds of flower- 

 ing plants. 



[The different interpretations placed upon the term ' spore ' and its derivatives by 

 different writers on cryptogamic botany present a great difficulty to the student. A 

 different terminology for the one followed here is now employed by some of the best 

 authorities ; but, in order to avoid the great alteration in the use of terms which 

 would otherwise be necessary, it has been thought best, in the present edition, to 

 retain Dr. Carpenter's terminology, at all events until a greater agreement has been 

 arrived at than is at present the case. ED.] 



