1881.1 



MICKOSCOPICAL JOL^RKAL. 



153 



general rule there is one exception. 

 In a weak solution of qimioleine blue 

 or cyanin, infusoria become col- 

 ored of a pale blue, and may continue 

 to live for thirty-six hours. The 

 color concentrates in the fatty granu- 

 lations of the protoplasm. It is very 

 faint in the sarcode expansions, in 

 vibratile cils, the cuticle and pulsat- 

 ing vacuoles. The nuclei escape 

 even more completely. Hence, it be- 

 comes easy to follow the phenomena 

 of the division of the nucleus in the 

 living animal undergoing division. 

 This coloring matter is one of the 

 best reagents for fatty matter. The 

 diverse reactions which it produces 

 in the same cell afford a new proof 

 of the difference in chemical compo- 

 sition of the cellular and nuclear pro- 

 toplasm. For these experiments an 

 aqueous solution of cyanin should 

 be used, which is very weak, but 

 strong enough. An alcoholic solu- 

 tion fixes the form of many species, 

 like osmic acid. This promises to 

 be a valuable reagent for physiologists 

 and histologists. 



o 



The Microscope and the Eyes. 

 — In the course of some reminiscences 

 of the late Dr. J. B. S. Jackson, Dr. 

 Oliver Wendell Holmes is reported 

 to have used the following words : — 



" Dr. Jackson would never meddle with 

 the microscope ; he was always contented 

 with his natural lenses of ten inches of 

 focal distance. And thus, whatever he 

 lost, he escaped one of the not infre- 

 quent effects of over-reliance upon the 

 instrument to which we are under infinite 

 obligations, but which is breeding a gen- 

 eration of intellectual myopes as one of 

 its results." 



When a man like Dr. Holmes 

 speaks in this way, it is but right that 

 he should explain his meaning and 

 state upon what foundation his asser- 

 tion rests. Does the proper use of 

 the microscope, even in the more 

 difficult fields of investigation, pro- 

 duce myopia, or any injurious effect 

 whatever, upon the eyes ? If there is 

 evidence to prove that it does so, we 

 would be glad to have Dr. Holmes 



bring it before our readers. We are 

 loth to believe that he would make 

 the assertion without convincing 

 proof of its accuracy. 



Protoplasm and Nucleus. — A 

 number of investigators have lately 

 given their attention to the structure 

 and functions of nuclei, in both ani- 

 mal and vegetal cells. The subject 

 is still very obscure, and there re- 

 mains considerable difference of opin- 

 ion as to the relative importance of 

 nuclei. However, the attention that 

 they have received has lately led to 

 many new discoveries. It has been 

 found that many plant-cells, which 

 were supposed to be destitute of nu- 

 clei, do possess them — sometimes 

 several in each cell ; but it is stated 

 that the Phycochromacese have no 

 nuclei. The following summary of 

 the views of F. Schmitz will prove 

 interesting in this connection : The 

 protoplasm of vegetable cells is a re- 

 ticulated framework of fine fibrillae. 

 In the youngest cells the peripheral 

 layers of the protoplasm are freely 

 dotted, while toward the middle are 

 homogeneous lacunae or vacuoles. 

 These increase, both in number and 

 in size, as the cell grows older, fre- 

 quently coalesce until the protoplasm 

 becomes reduced to a reticulated, 

 parietal utricle, with a number of 

 threads crossing the cell-cavity. Be- 

 tween the meshes there is a homo- 

 geneous fluid. The nucleus consists 

 of a matrix in which, after hardening 

 and coloring, a very fine punctation 

 can be recognized, probably due to a 

 reticulate structure. The nucleus 

 must be regarded as a differentiated 

 portion of the protoplasm ; its special 

 function appears to be the formation 

 of the proteinaceous substance. 



We are not yet prepared to sub- 

 scribe to all that has been written 

 about the reticulated structure of pro- 

 toplasm and nuclei, but prefer to wait 

 for more convincing demonstrations. 

 Mr. C. Fromman not only finds the 

 reticulated structure in the proto- 

 plasm in the chlorophyll-grains and 



