1888.] MICROSCOPICAL JOtJENAL. 147 



Cells and Protoplasm. 



By H. W. conn, 



MIDDLETOWN, CT. 



Modern microscopic methods have revolutionized our knowledge of pro- 

 toplasm and of the organic cell. Since the time when Beale wrote his ideas 

 on the cell, or when Huxley published his conception of protoplasm in his 

 ' Physical basis of life,' so much has been added to our knowledge that en- 

 tirely new positions must be taken, even by those who are inclinecl to accept 

 either of the two extremes. 



Formerly protoplasm was thought to be a very definite though a very com- 

 plex compound. The term physical basis of life was given to it under the 

 conception, that it was such a definite compound, always found where life 

 existed, and practically uniform. Indeed, to speak of a physical basis implies 

 that such a basis must be a definite substance and not a highly complicated 

 and variable one. But the modern microscope, modern methods of staining, 

 and modern careful study have changed all this. In the first place the seem- 

 ing homogeneity of protoplasm has been disproved. Instead of a simple 

 homogeneous jelly, the microscope now resolves it into a very complicated 

 structure. It may always be resolved into two parts, one which is the life- 

 substance, called the protoplasm proper; and the other, the food substance, 

 called the deuterplasm. The deuterplasm itself is a purely secondary sub- 

 stance, containing cell-sap, oil drops, food sphereis, etc. It is to the abun- 

 dance of this deuterplasm chiefly that the size of large cells is due. 



The protoplasm proper is itself very complicated. It has one universal 

 characteristic ; it is always reticulated. Sometimes the reticulum is quite 

 coarse and sometimes it is very fine. Its meshes are filled with the deuter- 

 plasm which supplies the protoplasm with its nutriment. The reticulum 

 itself is made of threads of a hyaline material, and in these threads or fibres 

 are embedded numerous extremely minute bodies which have been called 

 microsomata. Both the protoplasm and the microsomata are essential to the 

 protoplasm as is proved by their constant presence and by the peculiar 

 changes that they undergo during cell division. It is the changes in this 

 fibrous network and in the microsomata that constitute thp phenomena known 

 as karyokinesis. Now it is hardly to be supposed that the simplest sub- 

 stance to which life can be reduced should be of such a complex nature. It 

 seems much the more probable that one of these substances should be the 

 primitive one and by its action produce the other. If this is true there is 

 little doubt that the microsomata should be regarded as the primitive ele- 

 ments and the reticulum as secondary. Where there are these microsomata 

 there is life. These minute bodies are grouped together, differentiated in one 

 way and another, and by their different groupings give rise to the various 

 forms and properties of protoplasm. 



Chemically, too, our former dense ignorance of protoplasm is beginning to 

 disappear. Until recently about all that was known of it was that it was com- 

 posed of the elements, carbon, oxygen, hydrogen, and nitrogen, with other ele- 

 ments in small proportions. This was supposed to be united into a very com- 

 plex molecule which was beyond the power of chemists to analyze. As long 

 as only ordinary analytical methods were used it was impossible to discover 

 more. But recently microscopical chemistry has been developed, and has 

 already done something in the study of protoplasm with great promise of much 

 more in the future. No longer can we regard protoplasm as a single chem- 

 ical compound, but we must look upon it as a mixture of compounds. First, 

 there were distinguished chromatin (nuclein) and achromatin ; so named from 

 their ability to absorb staining reagents. The former is present chiefly in the 



