152 
Current  Literature. 
5  Am.  Jour.  Pharm. 
(  February,  1921. 
particular  sample.  Determinations  of  the  polarimetric  values  are 
made  by  soaking  3  grms.  of  the  powdered  air-dried  gelatin  in  cold 
water  for  30  minutes,  immersing  in  a  boiling  water  bath  until 
solution  is  complete,  cooling  to  35 0  C.  and  diluting  to  100  c.  c. 
If  clarification  is  necessary,  5  grms.  of  light  magnesium  carbonate 
are  added  to  the  solution,  which  is  kept  at  3040°  C.  for  an  hour, 
and  filtered  bright.  The  first  rotation  is  measured  in  a  200  mm. 
tube  at  350  C,  the  solution  then  being  kept  at  150  C.  over  night, 
and  the  rotation  again  observed  next  day.    The  results  are 
proportional  to  the  percentage  of  gelatin  required  to  produce 
a  standard  jelly  at  150  C.  This  standard  is  defined  as  a  solu- 
tion of  such  strength  that  a  bubble  of  air  4  to  5  mm.  diameter 
admitted  to  the  polarimeter  tube  moves  vertically  with  a  motion  of 
4  cm.  per  second.  Two  tables  are  provided,  giving  a  large  number 
of  results  obtained,  and  a  third  one  showing  the  comparison  between 
the  polarimetric  values  and  jelly  strengths  obtained  in  the  following 
manner:  A  6o°  funnel  is  partly  filled  with  mercury,  50  c.  c.  of 
the  gelatin  solution  are  poured  upon  the  surface,  and  allowed  to 
set  at  io°  C.  The  mercury  is  then  run  out,  and  a  partial  vacuum 
of  600  mm.  of  water  produced  below  the  jelly,  when  the  depression 
of  the  upper  surface  is  measured  by  a  micrometer  gauge.  The 
results  obtained  by  this  method  bear  a  moderately  definite  ratio  to 
those  given  by  the  polarimetric  method.  (From  The  Analyst,  No- 
vember, 1920.) 
Poisonous  Properties  of  Yew. — There  can  be  no  doubt  about 
the  poisonous  properties  of  the  yew ;  all  parts  of  the  plant  but  the 
arillus  have  been  shown  to  be  poisonous.  Yew  has  caused  the 
death  of  many  houses  and  cattle,  while  asses,  mules,  deer,  pigs,  rab- 
bits, and  pheasants  have  also  jpeen  poisoned.  In  "Plants  Poisonous 
to  Live  Stock,"  by  H.  C.  Long,  the  question  is  dealt  with  at  con- 
siderable length,  and  while  the  author  produces  much  evidence 
against  the  plant,  he  reminds  us  that  many  cases  have  been  recorded 
in  which  fatal  results  have  not  followed  the  ingestion  of  the  leaves, 
for  it  appears  that  the  lower  branches  of  yew  trees  in  parks  are  con- 
stantly cropped  by  cattle  without  ill-effects.  The  old  leaves  or  shoots 
are  mentioned  as  being  the  most  poisonous  parts.    Eaten  by  an 
expressed  by  the  formula 
Rotation  at  150 
— ,  and  are  inversely 
Rotation  at  35 0 
