THEIR AMOUNT OF WATER. 91 



to 74'45 in human muscles. These and similar determinations, 

 which have been instituted as to the muscles of different animals, 

 are not devoid of significance ; but as they vary even in the same 

 species of animals, they cannot attain any high degree of import- 

 ance until they can be compared with the quantity of water con- 

 tained in the blood, or, better still, with that in the blood-serum. 

 Thus, for instance, it would be highly important in reference to the 

 mechanical metamorphosis of matter, to ascertain the proportions 

 existing between the water contained in the muscles and that in 

 the blood under different physiological and pathological conditions. 

 A course of experiments, bearing on this subject, has lately been 

 instituted by one of my pupils. It was found that, on an average, 

 there are 9*9 less of water in the muscle than in the serum of the 

 blood, and that this proportion continues nearly the same whether 

 the blood was in a concentrated state or contained an excess of 

 water. This proposition, which is precisely what might have been 

 anticipated, was found to be fully confirmed in comparative ana- 

 lyses of the blood and muscle of persons who had died from cholera, 

 as well as in so-called hydraemic conditions. We may, unquestion- 

 ably, expect the most important results regarding the mechanical 

 metamorphosis of animal matter from investigations into the pro- 

 portions existing between the quantity of water contained in the 

 blood and the other juices, tissues, and organs of the animal body, 

 under different conditions. 



It will be readily understood that the determination of the 

 quantity of water contained in the muscles should be conducted 

 with the utmost care, as pieces of muscle very rapidly lose a certain 

 quantity of water when exposed to the air, and thus afford only a very 

 inexact result. Great care must be taken to avoid any evaporation 

 from the portion of muscle which is to be weighed. Another 

 circumstance which calls for attention is, that while the surface of 

 the piece of muscle, when placed in an air-bath or in a vacuum, dries 

 very rapidly, the interior obstinately retains its water. It should 

 moreover, be borne in mind, that it is not always easy to obtain a 

 portion of muscle alike poor in connective tissue and vessels, and 

 that the amount of connective tissue essentially influences the 

 quantity of water. In examining the muscular substance of the 

 human subject, the observation is rendered very much more diffi- 

 cult, from the circumstance that dissection must necessarily be post- 

 poned till eight or even fifteen hours after death, when endosmotic 

 currents may have been already established in the muscular sub- 



