8 ARON. 



40 per cent formaldehyde were added, the bottle closed and weighed again. In 

 the first experiment, the water content of each organ was determined. 



The blood from the large vessels, the heart, lungs, and other organs was collected 

 in a dish, which was weighed at the end of the experiment, after a known amount 

 of formalin had been added. A part of this blood-formalin mixture was preserved 

 in an air-tight bottle. 



The skin was carefully removed, all subcutaneous fat being left behind. As 

 yet no detailed analyses of the skin have been made. 



The brain was removed, weighed, and kept with formalin in the manner just 

 described. 



A more exact analysis of the bones seemed advisable in the course of the later 

 experiments, and a number of bones were carefully freed of all flesh and other 

 adhering parts. This waste material was carefully collected. The cleaned bones 

 were weighed and again preserved with formalin in a closed bottle. 



At this time about three hours may have elapsed since the death of the animal. 

 The remainder of the body, without skin, blood, organs, brain, and perhaps certain 

 bones, was weighed again and then cooked with a fair amount of water in a 

 large, weighed pot for from one to two hours. Following this operation the 

 meat and bones were separated with forceps and knife, the juice being left with 

 the meat. This separation generally required about half a day. Formalin was 

 then added to bones and meat. The weighings were accurate to 1 gram. The 

 bones were weighed on a large analytical balance, accurate to 0.1 gram. 



In experimenting with a trial animal, I added formalin before separating bones 

 and meat, but this procedure is not to be recommended, as the tissues around the 

 bones become so hardened that it is almost impossible to remove them. 



The bones preserved with formalin were dried on a hot day by exposure to 

 the sun on a large plate from morning to afternoon and the weight of the air- 

 dried bones was determined. 



The meat, juice, and formalin were evaporated to the consistency of porridge, 

 the total weight was determined, and the mixture placed in air-tight bottles. 



Both bones and meat, after they have been treated with formalin, retain so 

 much of this preservative that they are protected against decomposition. The 

 entire animal, after all the above processes have been accomplished, is well pre- 

 served and contained in eight or ten handy bottles, so that it may be analyzed 

 at leisure. 



The organs and the meat of the body are passed several times through a 

 sausage-meat grinder before analysis. Care must be taken not to lose any of 

 the fluid; but even if there is much of this before grinding, it is completely ab- 

 sorbed afterwards. No appreciable loss occurs if the grinding is done quickly and 

 the grinder then carefully cleaned. Seveial times I weighed organs before and 

 after grinding and found a loss of only 3 to 4 grams per kilo, which is of no 

 importance. Moreover, in our calculations, we assume that the total amount of 

 organs, meat, brain, etc., is the weight of those materials before being subjected 

 to the grinding process. We know the weight of the fresh organs. The formalin 

 added being absolutely volatile, we can determine solids, as well as fat, protein, 

 ash, etc., in the preserved materials and from these data we can calculate the 

 composition of the original, fresh substance. 



A difficulty in determining the weight of the entire skeleton arose from the 

 fact that the bones were divided into two parts, one cooked, the other uncooked. 

 It is not necessary to do this, but it seemed advisable in some instances. Only 

 such bones as occur in pairs in the body had been removed and analyzed sepa- 



