NOVEMBEK 29, 1901.] 



SCIENCE. 



845 



ever, and many of the fossil forms, show that 

 no clear line of separation can be drawn, 

 though the names are still retained for simple 

 convenience. 



The usual primary subdivisions of the Echin- 

 oidea into two subclasses, the Palseechinoidea 

 and Euechinoidea, have been abandoned and 

 the older divisions, Regularia and Irregularia, 

 adopted. The primitive ancestral Echinoid is 

 unknown, though it is evident that the first 

 forms were small sac-like bodies, with the 

 mouth and anus at opposite poles and the 

 muscular body supported by a series of angular 

 plates, of which five pairs were perforated by 

 pores. The thickening of the plates and the 

 consequent loss of flexibility is believed to ex- 

 plain the reduction in the number of vertical 

 rows taking place in the passage from paleozoic 

 to neozoic genera. ^ ^ Beechkr. 



Studien uher die Narcose, Zugleich ein Beitrag 

 zur allgemeinen Pharmakologie. By E. Over- 

 ton. Jena, Gustav Fisher. 1901. Pp. 195, 

 The chief object of these studies is the pres- 

 entation of a new theory of narcosis which 

 was put forward simultaneously but inde- 

 pendently by Overton and H. Meyer. The 

 essential point of the theory is that nar- 

 cotics are such substances which are more or 

 less soluble in the lipoids of the nerve cells, 

 chiefly cholesterin and lecithin. However, as 

 all substances reach the nerve cells only after 

 being taken up by the blood and the lymph, 

 they have in the first place to be soluble in the 

 chief medium of these fluids — i. e., water. The 

 question, therefore, whether and in what de- 

 gree a substance is a narcotic — i. e., whether 

 and in what degree it is able to enter into the 

 nerve cell — depends upon whether and how 

 much this substance is more soluble in fats 

 than in water ; in other words, the narcotic 

 vCapacity of a substance depends upon the co- 

 efficient of its solubility in organic solvents 

 divided by its solubility in water. 



The book consists of two parts. The first 

 part deals in an interesting and instructive way 

 with the general aspect of the subject of nar- 

 cosis. At the start the author shows that the 

 distinction made by Claude Bernard, Dastre 

 and other French writers, between anaesthetics 



and narcotics cannot be maintained. Neither 

 does the practical separation of the inhalation 

 anaesthetics from the other narcotics have a 

 scientific basis. There is, however, according 

 to the author, a distinct difference between in- 

 different narcotics and narcotics of a basic 

 character. The latter vary in their effects upon 

 animals as well as plants from species to spe- 

 cies ; while the indifferent narcotics affect all 

 vertebrates and some invertebrates in the same 

 degree, provided the concentration of the nar- 

 cotic within the blood of the animal is taken as 

 a basis for the unit, and not the quantity of the 

 narcotic used up in the production of the nar- 

 cosis of the animal. The writer discusses the 

 various steps which a narcotic has to pass 

 through from its administration to the animal 

 to its arrival in the body cells, and the different 

 modes of penetration of the several layers of 

 the cell, according to the compound employed 

 as a narcotic. He then describes in detail the 

 methods employed by Paul Bert, as well as 

 those employed by himself, to obtain a constant 

 concentration within the plasma of the blood 

 of the volatile as well as of the non-volatile 

 narcotics. 



The author reviews the different theories of 

 anaesthesia : hyperaemia, anaemia, Claude Ber- 

 nard's semi-coagulation of the protoplasm, 

 Dubois's theory of partial dehydration of the 

 protoplasm. He quotes further Eichet's rule 

 that a compound is the stronger an anaesthetic 

 the less soluble it is in water ; and after review- 

 ing our present knowledge of the presence of 

 cholesterin and lecithin in the nerve tissues, he 

 mentions that already as early as 1847 Bibra 

 and Harless have suggested that there might 

 be a connection between anaesthesia and the 

 capacity of the anaesthetics to dissolve fats ; 

 and that L. Hermann has further suggested 

 that cholesterin and lecithin of the ganglion 

 cells might present the point of attack of the 

 anaesthetics. 



Tai'ning to his own above-mentioned theory 

 Overton states that he studied the solubility of 

 the narcotics in olive oil, on account of the 

 difficulty of obtaining sufficient quantities of 

 lecithin, and describes in detail the physical 

 and physiological methods employed by him 

 for determining the division-coefficient (Thei- 



