726 



PHYSIOLOGY. 



however, from serum-albumen in its specific rota- 

 tory power, in its behavior on coagulation, and 

 in precipitability by certain neutral salts. Casein 

 and lact-albumen are the only proteids contained 

 in milk, the existence of such bodies described 

 as lacto-globulin, lacto-protein, peptone, and 

 hemi-albumose. having been predicated on faulty 

 methods of analysis. When milk turns spur 

 in consequence of the lactic-acid fermentation, 

 primary proteoses, chiefly proto-proteose, are de- 

 veloped. The proteid called whey proteid, which 

 is formed during the rennet fermentation, is not 

 of the peptone or proteose class, but should be 

 included with caseinogen in a new class of pro- 

 teids allied to the globulins. 



From experiments made upon sponges of 

 eighteen species by introducing various sub- 

 stances into the water of the aquarium Dr. 

 Lendenfeld, of Innspruck, finds that absorption 

 of food by them does not take place at the outer 

 surface, but in the interior; only foreign sub- 

 stances, used for building up the skeleton, enter 

 the sponge without passing into the canal system. 

 Grains of carmine and other matters often adhere 

 to the flat cells of the canals, but true absorption 

 only takes place in the ciliated cylindrical cells 

 of the ciliated chamber. These get filled with 

 carmine grains or milk spherules, but starch 

 grains prove too large for them. Remaining in 

 these cells a few days, the carmine cells are then 

 ejected, while milk particles are partly digested, 

 and then passed on to the migratory cells of the 

 intermediate layer. Any carmine particles found 

 in these latter cells have entered accidentally 

 through external lesions. The sponge contracts 

 its pores when poisons are put in the water ; and 

 the action is very like that of poisons on muscles 

 of the higher animals. Especially remarkable 

 is the cramp of sponges under strychnine, and 

 the lethargy (to other stimuli) of sponges treated 

 with cocaine. As these poisons in other animals 

 act indirectly on the muscles through the nerves, 

 it seems not without warrant to suppose that 

 sponges also have nerve cells which cause mus- 

 cular contraction. 



Muscular System. The experiments on mus- 

 cular tremor described by W. P. Herringham 

 were partly physiological and partly pathologi- 

 cal. They related to the tremors of voluntary 

 contraction, great effort, chronic cases, paralysis 

 agitans, lead tremor during effort, muscular 

 atrophy, ankle clonus, and those dependent 

 upon some rapid spinal lesion. The tremors of 

 voluntary contraction exist in connection with 

 a massive movement. In all willful contraction 

 the bone tends to move from the position of 

 rest. But there are tremors in which the bone 

 merely oscillates about the position of rest with- 

 out moving its mean point, and there is no mass- 

 ive action. On the hypothesis that tremor ap- 

 pears only as a characteristic of massive contrac- 

 tion, it is" easy to explain it. It appears because 

 this contraction is discontinuous. But, if that 

 be true, to say that it occurs without massive 

 contraction is to say that the mode of contrac- 

 tion occurs without the contraction itself. In 

 the tremor that occurs after great effort, the 

 trembling go on after the muscle has returned 

 to a position of rest. Yet this tremor, which is 

 not accompanied by a massive movement, must 

 be the same as the one which existed a moment 



before during the effort (in the case cited, a lift). 

 But if so, then tremor is not a mode of m 

 contraction, but something else different from 

 it, and which may exist without it as well as 

 with it. The explanation of the problem is 

 sought by the help of other facts known to us 

 about muscle. There are two properties in mus- 

 cle contractility and elasticity. In a healthy 

 muscle elasticity appears to be in constant ac- 

 tion. It is probable that contractility is also 

 constantly at work, and that there is a state 

 called tone due to this opposition. It seems 

 possible that the slight amount of voluntary 

 contraction which is thus inferred to exist may 

 be of a rhythmical character, and that the nor- 

 mal state of healthy muscle, when not undergo- 

 ing willful contraction, is one of slight to-and-fro 

 longitudinal movement due to rhythmical con- 

 traction followed by elastic extension, or perhaps 

 of slight alternating longitudinal and transverse 

 contraction. Something of the same kind serins 

 to occur in unstriated muscle. Assuming this 

 to be the case, this movement is invisible in ordi- 

 nary people when at rest ; but in a few persons 

 the naturally tremulous it can always be seen, 

 and in most others certain poisons tobacco 

 and alcohol, for example or states of general 

 exhaustion, such as sleeplessness, make it visible. 

 This alteration from the normal depends upon 

 increase of the rhythmical movement. If this 

 movement in normal conditions be supposed to 

 be caused by an exciting, and to be restrained by 

 an inhibiting nervous apparatus, then these ab- 

 normal rest tremors may be due to weakness, in- 

 herent or acquired, of the inhibitory apparatus. 

 A similar increase of longitudinal movement 

 causes the tremor of great effort or of fatigue 

 and lead poisoning. In these cases excessive 

 stimulation of the exciting apparatus for volun- 

 tary motion so exaggerates the movement as to 

 produce the curves which we see under these 

 conditions. It is suggested that the tremors of 

 rage and nervousness and those which occur 

 during fevers are of the first variety, due to weak- 

 ness of the inhibitory nerves, and that the seven 

 or eight per second movement of ankle clonus is 

 this same involuntary rhythm, exaggerated by 

 the sudden increase of tension and slowed by 

 the alteration in muscular elasticity which oc- 

 curs in these cases. 



The phenomena of voluntary and reflex mus- 

 cular contraction have been studied by J. Berry 

 Haycraft with reference to the theory that mus- 

 cular contraction is sustained by a series of im- 

 pulses discharged by the nerve element into the 

 muscular element so rapidly that the muscle has 

 not any time to relax between them, which the 

 author calls the " natural-tetanus " theory. The 

 general conclusions are drawn from the experi- 

 ments that during a reflex or a voluntary mus- 

 cular movement the muscles involved exhibit 

 fascicular or other local movements due to un- 

 co-ordinated discharge from the central nervous 

 system, and perhaps due also to variations in 

 excitability or activity of the fibers or fasciculi 

 affected. These contractions, although not rhyth- 

 mic, may occur with some rough average fre- 

 quency, and they cause the muscle sound which 

 has been remarked by some authors (Wollaston, 

 Paul Erman, Samuel Haughton. and Helmholtz), 

 which is a sensation produced by these move- 



