G. L. Kite 



glutinicity are exhibited by this substance. There are variations in 

 concentration of the nuclear gel that produce a characteristic but 

 misleading optical image. The nucleus appears to contain an irregu- 

 lar "network with granules imbedded in it. The interstices of the 

 network are very small luminous spots which have been misinter- 

 preted to be vacuoles. Many dissections have shown that the granules 

 are very concentrated masses of gel; the network irregularly disposed 

 masses of a diluter gel; and the interstices or light spots the most dilute 

 gel in the nucleus. The so-called network is a part of the nuclear gel 

 that forms a concentration gradient; the interstices and granules may 

 be considered constants connected by the grading network. It should 

 be clearly understood that the network is not made up of definite 

 threads of fibres but of irregular masses of hydrogel that are very 

 dense immediately surrounding the granules, from which they grade 

 into the dilute gel of the interstices. No free liquid was found in the 

 nuclear substance. 



When the granules are in focus they appear gray and cloudy or 

 opalescent; when out of focus as dark spots. They measure from 

 less than one to about two microns in diameter. 



It seems that a part of the luminosity of the interstices of the 

 network is due to diffraction and not simply to slight absorption of 

 light by this portion of the nuclear substance. 



The structural details of the nucleus can be brought out with con- 

 siderable vividness by staining with janus green (diethyl-safran in 

 azo-dimethyl-anilin) . 



Slight cuts in the surface of proteus qukkly close. Extensive 

 cuts frequently cause an ameba to explode in as short a time as 

 two seconds nothing but the nucleus may remain. If the contrac- 

 tile vacuole be cut and its liquid content caused to mix with the 

 cytoplasm the Ameba is immediately destroyed with explosive vio- 

 lence. A relatively large dose of distilled water and even | to i 

 molar cane sugar solution or one molar sodium chloride or potassium 

 nitrate give a like result. It is not usually possible to produce more 

 than a temporary vacuole with two molar cane sugar; a large dose of 

 sugar of this concentration usually causes the appearance of granules, 

 globules, fibrils and a hyaline appearance in any portion of the endo- 

 plasm into which the injection is made. The doses that were injected 

 varied from about 270 cubic microns to 30,000 cubic microns. 



