720  Estimation  of  Methyl  Alcohol  [^"^olZ^el^^ro. 
casts,  which  are  only  occasionally  covered  with  bacteria.  These 
casts  consist  entirely  of  bacteria,  usually  the  pyogenic  cocci,  closely 
packed  together.  They  are  differentiated  from  any  granular  debris, 
by  their  uniform  shape  and  size,  and  also  due  to  the  fact  that  they 
are  easily  stained  with  aniline  dyes. 
Calcareous  Casts. — There  are  few  cases  on  record  where  true 
casts,  exact  moulds  of  the  renal  tubules,  were  observed  in  the  urine 
of  adults  suffering  with  diseases  leading  to  the  formation  of  renal 
calculi.  These  were  found  to  be  either  the  phosphate  or  carbonate 
of  calcium. 
Ammonium  Urate  Casts. — Casts  giving  the  reactions  of  ammonium 
urate  have  been  met  with  in  the  urine  of  the  new-born  and  other  in- 
fants. According  to  many  observers,  their  presence  seems  to  have 
very  little  significance  as  a  distinguishing  feature  in  diseases. 
Spermatic  Casts. — These  have  been  reported  by  some  in  cases  of 
spermattorhea.  They  are  said  to  closely  resemble  hyaline  casts, 
except  that  they  are,  as  a  rule,  much  longer  and  broader.  The  ap- 
parent absence  of  albumin  is  an  important  fact  for  differential  diag- 
nosis. No  one  has  as  yet  established  clearly  the  origin  of  these 
casts. 
Pseudo  Casts  are  bodies,  of  varied  inorganic  or  organic  origin, 
possessing  somewhat  a  resemblance  to  true  urinary  casts,  and  may  be 
mistaken  at  times  by  the  inexperienced  for  true  casts.  Unlike  the 
latter,  these  false  casts  have  no  definite  relationship  to  renal  dis- 
orders. Masses  of  urates,  phosphates,  oxalates,  uric  acid  and  other 
crystals,  deposited  on  shreds  of  mucus,  or  crystallizing  on  other 
filamentous  structures,  produce  forms,  distantly  resembling  casts. 
The  use  of  heat  and  appropriate  microchemical  reagents  and  prac- 
tice will  soon  allow  the  inexperienced  to  avoid  these  as  a  source  of 
error. 
A  NEW  METHOD  FOR  THE  ESTIMATION  OF  METHYL 
ALCOHOL.* 
By  S.  B.  Schryver  and  Cyril  Christian  Wood. 
A.  Estimation  of  Methyl  Alcohol  in  Water. — Some  years  ago, 
one  of  the  authors  described  a  method  for  the  detection  of  formalde- 
hyde, which  could  be  applied  to  the  quantitative  estimation  of  very 
small  amounts  of  this  substance  {Proc.  Roy.  Soc,  1910,  B.  82:  226, 
*From  The  Analyst,  May,  1920. 
