158 ROYAL SOCIETY OF CANADA 



tion^ of Browicz/ who injected intravenously in a dog a quantity of a 

 solution »f Merck's liannoglobin and found crvstals of haemoglobin in 

 tlije hepatic nuclei. He observed also, that when red corpuscles break 

 down in liver cells, hœmoglobin is stored in their nuclei, and this can 

 (Only be explained on the assumption that ha^mogl(>l)in dill'ust^ through 

 fthe nuclear membrane. 



One may multiply tJie instances, but enough are detailed to show 

 that niiembrones in, and tlie protoplasm of, the living oell are capable of 

 allowing " colloids " to diffuse through them, and that living animal 

 membranes do not necessarily distinguish between cx>lloids and crystal- 

 loids, unless they are specially constituted for tliat purpose, and then, 

 atrange to say, they tend to be impermeable to ciystalloids of the inor- 

 ganic class. 



One of the most striking result's of my micrqchemical s^tudies is the 

 determination tliat the nucleus is .absolutely free from chlorides and 

 phosphates, and as these fonn the typical salts of sodium, potassium, 

 calcium and magnesium in tissues and physiological fluids it is obvious 

 that these elements are absent also from the nucleus. Indeed, direct 

 tests for potassium and calcium show unmistakably that salts of these 

 elements do not occur in the normal nucleus. 



It is a fact that in the intestine absorbing iron salts the nuclei of 

 the epithelial cells whose cytoplasm gives a marked reaction for inorganic 

 iron are wholly free from inorganic iron. In fact, the whole 

 icyiioplasm may be surcharged with inorganic iron and yet not a trace is 

 found in tlie nucleus. Even in the liver in pernicious amemia, when (the 

 cytwplasm of the hepatic cells is markedly impregnated with inorganic 

 iron, their nuOlei never show a trace of it. 



From thet?.e and other observations, I put forward the doctrine tliait 

 the normal cell nucleus does not know tlie inorganic world, that it is 

 tihe home of certain organic compounds only. 



Is this merely due to' the greater avidity of the cytoplasm for inor- 

 gianic salts and thus none of the latter are allowed to leave the cytoplasm 

 for the nucleus, or does the nucleus offer of itself an obstacle to the pene- 

 tration of it by inorganic salts? 



The latter is, I believe, the correct answer. The head of the sper^ 

 matozoon is an altered nucleus and in the seminal fluid apart from the 

 spermatic elementis there are the chlorides of sodium and potassium. 

 Now, if the cytoplasm is responsible for the freedom of the nucleus from 

 inorgianic compounds, the head of the speTma;tozoon should be charged 



'Bull, internat, de I'Acad. des Sciences de Cracovie, July, 1899. 



