452 



Mr. W. North. The Influence of 



last for several experiments, and this was weighed out into paper 

 bags in quantities sufficient for each day's consumption, an allowance 

 of 10 grams on each day's quantity being made for loss in the 

 process of making. This figure was arrived at by actual experiment. 

 It will be obvious that by this method, the bread being always made 

 in the same way and from precisely the same quantities of the same 

 ingredients, analysis of the flour was sufficient to determine the daily 

 quantity of each constituent, the weight of the bread itself being 

 quite immaterial. I may add that it was raised by means of bicar- 

 bonate of soda and tartaric acid, and baked in tins to avoid possible 

 loss in the procesSj and that the greatest care was taken to ensure the 

 consumption of the whole daily quantity by keeping it in paper bags, 

 so that no crumbs were lost. 



In this way I secured absolute uniformity as regards bread. 



Meat. — The difficulties to be evercome in order that the meat might 

 be made to fulfil the conditions already laid down were much more 

 serious than in the case of bread. They were, however, successfully 

 met by my friend Mr. Stephen Darby, of Leadenhall Street, to whom 

 I would here express my great obligation for the service he has ren- 

 dered me in this matter. The process of preparation is briefly this : — 



A large quantity, 80' to 100 lbs. of selected lean beefsteak, was 

 carefully freed from all obvious fat, tendon, &c, cut into pieces about 

 the size of a Barcelona nut, and dried upon a steam floor for some 

 time, then cut into still smaller pieces and dried again, and the pro- 

 cess repeated until the material was dry enough to be finely ground 

 in a mill. The resulting powder was exceedingly dry, of about the 

 consistency of building sand, practically insoluble in water even 

 after very prolonged boiling, but readily attacked by very dilute 

 hydrochloric acid (0*2 per cent.), and apparently very easy of diges- 

 tion. 



I found that the insolubility of the material somewhat interfered 

 with the palatability of the soup made from it (in which form it was 

 always taken but by the addition of vegetables and seasoning). This 

 difficulty was surmounted, as was also another, viz., that the powder 

 would not remain in suspension unless something were added to 

 thicken the soup. It will be obvious that this meat powder fulfils 

 the required condition almost perfectly. It will keep almost inde- 

 finitely (I have used some recently which was made nearly four years 

 ago). It is of uniform composition, and can be very readily analysed 

 — one analysis therefore sufficing for a very large number of expe- 

 riments. 



Potatoes. — There is no difficulty as to these, " Edwards' patent 

 desiccated potato" fulfilling every condition perfectly. 



Green Vegetables. — These were for a long time a source of very 

 great trouble. At first I used ordinary fresh vegetable, which was 



