576 
Progress  in  Pharmacy. 
/Am.  Jour.  Pharm. 
I   December,  1903. 
Probably  the  most  comprehensive  and  complete  contribution  on 
the  subject  that  has  been  published  up  to  this  time  is  the  series  of 
articles  now  appearing  in  the  current  numbers  of  the  Chemical  News, 
constituting  a  "  Thesis  on  Radio-active  Substances  Presented  to  the 
Faculte  des  Sciences  de  Paris,"  by  Madame  Sklodowska  Curie. 
In  this  thesis  Madame  Curie  reviews  the  whole  subject  of  radio- 
active matter,  and  records  in  detail  the  work  done  by  herself  and 
her  husband  on  polonium  and  radium. 
In  discussing  radium,  Madame  Curie  gives  the  following  character- 
istics: "  The  salts  of  radium,  chloride,  nitrate  and  sulphate  resemble 
those  of  barium  when  freshly  prepared,  but  they  gradually  become 
colored.    All  radium  salts  are  luminous  in  the  dark. 
"  In  their  chemical  properties  the  salts  of  radium  are  absolutely 
analogous  to  the  corresponding  salts  of  barium.  However,  radium 
chloride  is  less  soluble  than  barium  chloride  ;  the  solubility  of  the 
nitrates  in  water  is  approximately  the  same. 
"  The  salts  of  radium  are  the  source  of  a  spontaneous  and  continu- 
ous evolution  of  heat." 
The  radiations  from  radio-active  bodies  are  of  a  complex  nature. 
Rutherford  designates  them  as  at  ft  and  y  rays. 
I.  The  a-rays  are  very  slightly  penetrating  and  appear  to  consti- 
tute the  principal  part  of  the  radiations. 
These  rays  are  readily  absorbed.  They  are  slightly  deflected  in 
a  strong  magnetic  field. 
II.  The  /9-rays  are  less  absorbable  than  the  a-rays.  They  are 
deflected  by  a  magnetic  field,  in  the  same  way  as  cathode  rays. 
III.  The  ^-rays  are  penetrating  rays,  unaffected  by  the  magnetic 
field  and  comparable  to  the  Rontgen  rays. 
One  of  the  most  interesting  announcements  in  connection  with 
radium  was  that  recently  made  by  Sir  William  Ramsay,  who  asserted 
that  the  radium  emanations  appear  to  consist  of,  or  to  produce, 
helium,  one  of  the  recently  discovered  inactive  gases. 
Food  preservatives  have  also  continued  to  attract  considerable 
attention  during  the  past  year.  This  is  particularly  true  of  Euro- 
pean countries,  where  laws  prohibiting  the  use  of  a  number  of  these 
substances  have  been  enacted.  In  our  own  country  the  Department 
of  Agriculture  has  instituted  an  extensive  series  of  experiments  to 
determine  the  toxicity  of  the  several  chemical  substances  usually 
used  as  food  preservatives. 
