434 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vo.. VIIL. 
the number of atom-groups forming part of the chain and it is, therefore, 
not inconceivable that having determined how many examples of each 
there is in the peptone chain, the artificial production of the latter in 
the laboratory may soon be effected. The production of peptones in 
this manner would lead eventually to the synthesis from them of 
proteins. 
The results achieved so far show that the constitution of proteins 
is no longer an insoluble mystery and that their manufacture in the 
laboratory is not an impossible event. The presence of these amino- 
acid radicals in vegetable as well as in animal proteins indicates that 
biochemical synthesis proceeds in the same way in both kingdoms and 
that practically the same construction material is used. As proteins 
are the material of which the material basis of life is constituted it is 
manifest that if we could explain how proteins first arose without the 
participation of living matter in the synthetic act we might be in a 
position to explain the origin of living matter itself. 
The simplest proteins that we know are protamines which are _ 
found in the heads of the sperm cells of fishes and united there with a 
special compound of phosphorus known as nucleic acid. The compound 
in the heads of the sperm cells is responsible for the functions the sperm 
cells perform and it is the physical basis of the life of the sperm ele- 
ment. Some of these protamines are constituted of diamino acids only 
and are thus practically compounds intermediate between peptides and 
proteins but their chief significance is that they show that complex 
vital processes can function in such comparatively simple compounds, 
that is, the molecular constitution with which vital processes are 
associated may be of a comparatively simple kind. 
The simplest proteins, that is, protamines, as well as the most 
complicated and highly organized proteins do not form true solutions 
with water but rather what is known as colloidal suspensions, suspen- 
sions, however, in which the particles suspended or held in the fluid are 
of so minute a size that they cannot be seen with the highest powers 
of the microscope. The limit of microscopic vision is about 0.14 of a 
micron, that is, of one thousandth of a millimetre. An object more min- 
ute than that or under one-one hundred and seventy-five thousandth 
part of an inch cannot be seen. To have, therefore, any evidence, that 
in solutions of proteins the latter are in the form of suspended particles 
one must employ the ultramicroscope, that is, a modification of the 
microscope which will reveal the presence of such particles in practically 
