Notes on Dr. Abbe s Letter. 239 



ble, identical effects upon all the specimens treated by each re-agent, 

 using the same solutions for the same periods upon them all. By each 

 method nuclei were clearly demonstrated in the turtle's blood, but in 

 no other specimen was there any differentiation of color. It is true 

 that some mammalian corpuscles, after prolonged immersion in the 

 coloring fluid, showed staining, but that staining was invariably uni- 

 form from center to circumference, proving conclusively the absence 

 of a nucleus so far as carmine staining can prove anything. 



On these observations I base a strong suspicion that the alcohol and 

 corrosive sublimate used are responsible for the appearance of nuclei 

 in corpuscles treated by Bottcher's method. This suspicion receives 

 support from recent discoveries as to the structure of nuclei. In the 

 July number of the Quarterly Journal of Microscopy Dr. Klein 

 relates a series of observations, as a result of which he affirms the 

 nucleus to consist of a fibrillar network, imbedded in which is a 

 .ground substance ; that this intranuclear network is continuous with a 

 similar intracellular network ; that nucleoli are merely the thickenings 

 and shrivelings of these fibrils. The natural shriveling effect of 

 alcohol might readily produce a pseudo-nucleus in a blood-corpuscle 

 from condensation of this intracellular network. 



Physiological Laboratory, W. T. Belfield, M. D. 



Rush College, Chicago, March 4, 1879. 



NOTES ON DR. ABBE'S LETTER. 



{^Received January 2gt/i.) 

 I am truly sorry that Dr. Abbe has so far misunderstood my remarks 

 upon the Zeiss ^-g-inch, as to suppose that I intended to question M 

 Zeiss's veracity when I said that " so far as could be judged from out- 

 side appearance, it is a 'three system' objective." I did not mean to 

 say dogmatically that it was a " three system." Though I had no copy 

 of M. Zeiss's circular, I was aware that, when the new oil immersions 

 were first announced, they were mentioned as four systems, but 

 then they were also mentioned as having a balsam angle of 115° to 

 1 16°, and as the objective in my hands, as measured by the Spencers 

 and myself, and by Mr. Tolles and the owner of the objective, as I am 

 informed by the latter, was barely 102°, I might be pardoned for sup- 

 posing that, possibh', this particular yi-inch. was from a new formula of 

 Dr. Abbe, and a " three system." I did not mean to say positively that 

 it was not what is called a four system. Certainly if it had been a 

 three system, there would have been far more credit to be given to the 

 distinguished mathematician and to the optician, whose combined skill 

 had produced so perfect an objective, inasmuch as a four system is the 

 more easily corrected. However, I beg to disclaim any thought of 

 questioning M. Zeiss's assertion that the new objectives are four 

 systems, and I am truly sorrj- that Dr. Abbe has so understood me. 



