n6  Animal  Digestive  Ferments.  {^il^^S^' 
first  (or  necessarily  at  all)  to  be  considered  as  to  whether  it  is  a 
"  clear,"  visibly  compatible  preparation;  its  value  can  only  be  ascer- 
tained by  submitting  it  to  actual  assay;  that  is  to  say,  a  fluid  prepara- 
tion must  be  tested  by  precisely  the  same  means  as  the  dry  ferments. 
The  preparation,  then,  should  have  such  stability  as  to  reasonably 
ensure  its  coming  into  medicinal  or  technical  use  in  a  proper  form, 
assuming,  always,  that  it  will  receive  a  proper  degree  of  care  in  con- 
sideration of  its  organic  nature;  that  it  will  not  be  exposed  to  heat, 
and  that  a  proper  rotation  of  supply  will  be  observed. 
The  therapeutic  use  of  the  digestive  enzymes  in  the  peptonization 
of  food  is  based  upon  purely  physiological  grounds,  differing  from 
ordinary  alimentation  only  in  the  degree  and  extent  to  which  the 
food  is  pre-fkted  for  assimilation  when  exhibited. 
The  chemico-physiological  investigations  as  to  the  physiological 
reaction  of  the  proteids,  their  cleavage  products  and  derivatives, 
when  introduced  into  the  system  otherwise  than  by  the  gastrointes- 
tinal tract,  interesting  and  practical  as  they  are  in  advancing  the 
domain  of  our  knowledge,  so  far  throw  no  light  on  the  normal  or 
abnormal  processes  in  the  body,  and  have  presented  no  ground  in 
the  mind  of  any  investigator,  we  believe,  for  any  conclusions  or 
theories,  of  significance  in  practical  medicine.  Especially  unfounded, 
for  instance,  is  any  assumption  that  the  more  soluble  proteids  of 
digestion  may  be  considered  less  valuable  than  the  native  or  par- 
tially converted  proteids. 
We  know  well  the  composition  and  value  of  the  native  food, 
and  the  nature  and  object  of  the  digestive  conversion.  Wide 
experience  has  well  determined  that  a  normal  dietary  must  con- 
tain the  varied  elements  of  food,  and  in  proper  nutritive  balance, 
and  that  the  most  minute  elements  thereof,  even  the  inorganic, 
exert  a  marked  influence  upon  the  acceptability  and  digestibility  of 
the  foods  with  which  they  are  associated. 
The  solution  of  food  is  essential  to  its  availability  for  nutrition, 
and  by  means  of  the  animal  enzymes  it  became  for  the  first  time 
possible  to  prepare  fluid  food  actually  containing  the  entire  digest- 
ible solid  in  solution  in  a  non-coagulable  form,  thus  utilizing  in 
the  feeding  of  the  sick  the  normal  typical  foods,  farinaceous  and 
proteid. 
The  instinctive  repugnance  to  solid  food  in  disease  has  in  itself 
led  to  the  evolution  of  diet  in  therapeutics,  and  the  peptonized  foods 
