1891.] MICKOSCOPICAL JOUEISAL. 209 



formance of definite purposes, and these form systems, the various 

 organs of which so interact as to utilize the activity of each to the best 

 advantage. The regulation of the various activities is called co-ordina- 

 tion. It is a form of activities of the function of irribility , and is present 

 in some degree in all beings, but is most perfect in the highest. Thus, 

 for instance, the human heart is an organ chiefly composed of motile 

 tissue or muscle. The heart has such a shape that when the muscle 

 contracts fluids in it will be expelled ; to cause the expulsion in the di- 

 rection most favorable to the work of all the tissues of the body, valves 

 of tendinous tissues are placed in various parts of the heart ; but, further, 

 the amount of fluid expelled will depend on the degree of contraction of 

 heart tissue, and this on the degree of activity of the cells, which will 

 in turn depend on the degree to which they are irritable, and that to 

 which they are irritated. Now, the other tissues need to have the heart 

 expell varying amounts of blood ; when they are all at rest, as in sleep 

 not very much blood is needed ; but when a good deal of work is being 

 done by any tissues then much is required. Unless some connection is 

 established to adjust the heai-t's work and the tissues' work, the heart 

 may overwork, or the tissue be imperfectly supplied, or both. In the 

 highest animals the mutual operations of tissues are very perfectly ad- 

 justed to each other, so that there is none of what mechanics would call 

 lost motion. We have a second good illustration of co-ordination in 

 the digestive system. We do not secrete saliva all the time, but only 

 when we need it, as when we are about to eat something or are using 

 the mouth in speech. The eye secretes abundant tears if we get some 

 dust in it, and these help us to remove the cause of irritation. The 

 pancreas and all digestive glands work only when they are being used, 

 and rest at other times. Their co-ordination makes this possible. 



Resume. We have now considered protoplasm audits powers, the 

 cell and the mode of cell activity, the consequence of the aggregation of 

 cells in large masses in tissues, division of labor and co-ordination. 



\To be co?itt9iued.'\ 



Sterilized Milk for the Poor.— The Brooklyn Diet Dispensary 

 now furnishes, for the use of hand-fed infants or adults requiring it, 

 the best quality of cow's milk, thoroughly sterilized, in small Soxhlet 

 bottles, containing sufficient milk, when diluted, for two feedings. — 

 Brooklyn Med. Jour .^ July ., i8gi. 



The Healthy Tonsil Does not Absorb —Experiments recently 

 made by Eugene Hodenpyl, and recorded in the Am. Jour. Med. 

 Sciences io\- March, 1891, tend to show that the surface of a healthy 

 tonsil does not readily absorb substances brought in contact with it. 

 Such substances as olive oil, melted lard, lanoline, carmine, etc., v^ere 

 smeared over the tonsils of animals, allowed to remain from fifteen 

 minutes to an hour, and then the animals were killed, and a microscop- 

 ical examination of the tonsils made. In no case had any absorption 

 taken place. 



But if the epithelial layer be destroyed, or greatly thinned, and thus 

 the substance be brought into contact with the lymphatics, absorption 

 takes place. 



