DATURA STRAMONIUM AND D. TATULA. 
31 
In this equation, the small quantity of sulphur in albumen is viewed as oxygen. The 
simplicity of the equation is remarkable ; for, of the two forms of carbonic acid produced, 
the one, amido-carbonic acid, passes away per vesicam , and gaseous carbonic acid per 
halitem. Seven times as much carbon should appear in the latter as in the former secre¬ 
tion, and this is exactly what has been found in the case of dogs fed with flesh free from 
fat. Using Andrew’s units of heat and the above equation, one ounce of transformed 
tissue (28’35 grammes) would raise 126'5 kilogrammes of water 1° C., or converted into 
its mechanical equivalent by Joule’s number 425, would raise 53,762 kilogrammes one 
metre high.* These numbers are easily applied. Soldiers during peace are well exer¬ 
cised by a march of seven miles daily. Their useful external work is therefore 38,333 
metre kilogrammes; while the potential energy in the 3‘94 oz. of flesh-formers (remain¬ 
ing after deducting the amount in the alvine evacuations) is 211,822 metre kilogrammes. 
But the internal dynamical work of the heart, respiratory and other movements, require 
107,524 metre kilogrammes, so that the residue of 104,298 metre kilogrammes represents 
nearly three times as much potential energy as useful work. The same method of calcu¬ 
lation being applied to a labourer, shows that the 3'5 oz. of flesh-formers, applied to ex¬ 
ternal dynamical work, would, after deduction, yield 172,125 metre kilogrammes, the 
useful work of the labourer being 109,496 metre kilogrammes. 
The speaker then showed that the fat contained in the muscles was quite insufficient 
to account for the useful work done. While the wasted muscles of a non-labouring man 
would yield 506 kilogramme units of heat, the fat resident in them would give only 87 
kilogramme units. 
The third division of the discourse treated of the secretions as measures of work. A 
man living on a subsistence diet should excrete 267 grs. of urea daily, and we find that 
264 grs. have been actually found under such circumstances. Soldiers on the diet of 
peace should have from 560 to 580 grains of urea in their excretions, and the mean of 
Haughton of 575 grs. represents this quantity. An active labourer ought to have 735 
grs. of urea in the urine, and forgemen in engineering works were found to have 740 
grains, while active pedestrians were found to have as much as 800 to 850 grs. The same 
people on days of rest, as on Sundays, had only 500 grs. 
The amount of nitrogen secreted per otnum was viewed as the measure of digestive or 
assimilative work. One-twelfth of the flesh-formers consumed in food pass away in a 
state of health in the alvine evacuations as exhausted digestive ferments. These, the 
speaker contended, were merely slightly oxidized flesh-formers, ready for assimilation, and 
secreted to prepare the food for absorption into the blood. A small portion of them were 
exhausted in the act, and were then excreted per anum , but much the largest portion was 
reabsorbed into the blood, and was used for the formation of tissues. 
In bad digestion, or with excess of food, more than one-twelfth of the flesh-formers is 
necessarily found in the alvine evacuations. 
DATURA STRAMONIUM AND D. TATULA. 
The following is given in connection with the spontaneous return of hybrid plants to 
their parental forms, and is also interesting from the fact that both are now in use for 
medicinal purposes. 
Naudin maintains that hybrid plants, however constant at first, tend in subsequent 
generations to a separation of the two specific elements, which are, as he expresses it, 
rather intermixed than truly combined, so that they would at length resolve themselves 
into the two parental types, or by failure on one side return to the one or the other. In 
the ‘Flore des Serres ’ for July, 1864, he gives the results of his experiments upon our 
common sorts of thorn-apple, Datura Stramonium and D. Tatula. These have more 
commonly been taken for varieties of one species ; but their specific distinction has been 
maintained, especially of late, by various arguments. According to Naudin, they are 
truly distinct species which do not sensibly vary. One always exhibits green stems and 
* In this estimation the carbon in urea is supposed to be oxidized into carbonic oxide ; 
but it would be still more in favour of the view if urea were taken as the residue, and six 
atoms more of hydrogen were oxidized. 
