38 THE A3IERICAN MONTHLY [Feb. 



or a cellular structure to which poisons would be deadly 

 in their effect. The process of encroachment of an aniline 

 dye and its lethal results may be .studied with equal in- 

 terest in the smaller Navicula3 as iu tlie lar^u^er. There is 

 the same activity of irritation and arresting" of locomo- 

 tive power, and finally the death of the bioplasmic 

 power, whether inside or outside of the frustule. For 

 those who could find interest in tlw death struggles of" 

 vertebrate animals, as seen in the case of Spanish bull 

 tights, or the asphyxiation of dogs during the canicula, 

 might be found plenty of mental excitement in following 

 the death throes of a diatom from start to finish, under 

 the method of drowning in a weak aniline bath. 



After having had sufficient familiarity with the phases 

 leading up to the extinction of the life process of a series 

 of living diatoms in the field of the microscope, it would 

 perhaps be repugnant to the student to admit that he has 

 been witnessing vital phenomena characteristic alone in 

 its nature of plant or vegetable life. These forms have 

 heretofore been deemed too insignificant to warrant for 

 them a place among the Protozoans; the fundamental or 

 simplest class of animal life which modern science has so 

 far been able to trace. 



By varying the dyeing tests with a substitution of com- 

 mon violet writing ink, I found features not observed dur- 

 ing a lengthy study with methyl blue. When the violet 

 stain reached the Navicula, I noted that what appeared to 

 be a sort of vermicular festoon was formed from the man- 

 tle or surface of the frustule, and the vermicular shreds 

 broke off and drifted away leaving some strands adher- 

 ing to its sides and small villous tufts at each end of the 

 frustule. This seemed to represent to me, what C. Onder- 

 donk described as the mantle expanding or crinkling 

 up like folds of cloth around the edges of the frustule. 

 Apart from this, I found nothing that I could identify 

 as that which he stated he had repeatedly verified iu re- 



