No. 2.] CHANGES IJV NERVE CELLS. 113 



the microscope?" He proceeds to answer the question under 

 the idea that staining reveals much finer differences than 

 changes of form. This determines his method, which consists 

 in choosing two frogs of the same weight and sex, the one to 

 be experimented with, the other to use as control. He then 

 stimulates by induction, shocks the eighth nerve of one frog for 

 one hour, keeping the control frog as quiet as possible during 

 the same time. The spinal cords of both are now removed 

 and hardened in corrosive sublimate solution and alcohol, and 

 sections are made through both, opposite the origin of the 

 eighth nerve. The sections are stained on the slide with hae- 

 matoxylin, nigrosin, eosin, and safranin (the Gaule combina- 

 tion), in the order named. In some cases, the author states, 

 sections of the two cords were treated on the same slide. Here, 

 again, interest is attracted to the nuclei. By a difference in 

 staining these fall into two categories, the red and the blue, 

 and a greater proportion of the nuclei stain red in the cord of 

 the stimulated frog. A count of all red and all blue nuclei, in 

 a large number of sections, shows that from 3.31 to 3.66 times 

 more nuclei stain red in the stimulated than in the unstimu- 

 lated frog. The results are derived from but four frogs, two 

 stimulated and two control.^ 



Reproductive tissues, gland, muscle, and nerve have thus 

 been worked, with a purpose of demonstrating microscopical 

 changes connected with functional activity. The above is itself 

 a resume. I shall not attempt a resume of a resume. I wish, 

 however, to gather in a few words the ideas having special bear- 

 ing upon my own work. 



1. In connection with reproduction, the nucleus of the fertil- 

 ized ovum determines the form of the whole animal. Each 

 nucleus determines the protoplasm of its own cell. 



2. Protoplasm may be of the nature of a stable mechanism, 



1 For reasons detailed in a previous paper I do not place entire confidence in the 

 above results (24, p. 384). Such a difference may be due to the frogs for so small 

 a number of cases, but is more probably due to a difference in thickness of sections, 

 as I have found that thick and thin sections stain differently in exactly this respect, 

 the nuclei near the surface of the section staining red, those deeper down staining 

 blue. Hence the thinner the section the greater the proportion of red-stained nuclei, 

 and in equal areas of section Daszkiewicz finds nearly 400 (4127 to 3759) less nuclei 

 in the stimulated cord. This would indicate that these sections are thinner, and here 

 he finds the preponderance of red nuclei. 



