348 



SCIENCE 



[N. S. Vol. XXXVI. No. 924 



author gives the historical development which 

 finally leads to the establishment of the identity 

 of the enzymes pepsin and rennin, and sug- 

 gests that curdling of milk is best explained 

 by supposing that the curd is formed by the 

 precipitation of a proteose of casein which is 

 insoluble in acids and in water containing 

 calcium salts. Cohnheim sadly but humanly 

 remarks, " We meet here with one of the un- 

 fortunate cases in which science in stepping 

 forward obliterates and renders useless the 

 hard and skilful work of a whole generation 

 of prominent men." 



Of interest are the oxidative enzymes lac- 

 case and tyrosinase, which convert the aro- 

 matic cleavage products of protein into color- 

 ing matters which gradually become black. 

 Laccase, of the lac tree, gives rise to oxyu- 

 rushic acid which gives the brilliant black 

 luster to the lacquer manufactured in Japan 

 and China. Tyrosinase causes the production 

 of coloring matter in the hemolymph of cer- 

 tain butterflies, it also attacks the proteins of 

 the dead or dying leaves in the autumn and 

 causes the brilliant coloring of the Indian 

 summer; it is found in the ink-bag of the 

 sepia; and to it may be ascribed the trans- 

 formation of tyrosin into homogentisic acid 

 in the human disease of alcaptonuria. 



Written primarily for medical students, the 

 above selections are merely an indication of 

 the breadth of view from which the subject is 

 surveyed. 



The country should be grateful to Professor 

 Cohnheim that, through the means of the 

 Herter Lectureship Foundation, he has been 

 able to add to its literature a treatise such as 

 is " The Enzymes." 



Graham Lusk 



SPECIAL ABTICLES 



SYMPTOilATIC DEVELOPMENT OP CANCER 



So little is apparently known of the external 

 symptoms of internal cancer in its early stages 

 that any contribution of attentive observation 

 would seem useful. The following personal 

 case is fairly paralleled by another which need 

 not be described; and the parallelism would 

 seem to give some weight to the inferences. 



During my second expedition to Seriland 

 in the autumn of 1895 my party had occasion 

 to climb Sierra Seri, the culminating range of 

 the region. After leaving the wagon camp 

 the party moved on foot (with two pack ani- 

 mals) over some 10 miles of gently upsloping 

 plain to the foothills, where the real climb 

 began; the pace taken was rather rapid and I 

 was somewhat but not excessively tired on 

 reaching the foothills, where the pack horses 

 were to be sent back. Within a few minutes 

 after starting the climb I observed a condition 

 novel in my experience — i. e., inability to lift 

 the feet (especially the left) more than a few 

 inches above the level at which I stood. There 

 was no pain, scarcely any discomfort — merely 

 the inability to raise the feet without help 

 from the hands. Assuming it a manifestation 

 of exhaustion, I halted the party for a time 

 and ate lunch; but, on resuming, the condi- 

 tion almost immediately returned. Greatly 

 puzzled, I abandoned the climb and started 

 back with the Indian in charge of the pack 

 horses, finding no difiiculty in going down- 

 slope. Within fifteen minutes I was startled 

 by a call from one of the remainder of the 

 party making the climb, " El Gringo es muerto 

 [The American is dead]." Even without ex- 

 planation I knew this referred to W. D. John- 

 son, topographer of the expedition; and stimu- 

 lated by the apparent tragedy I immediately 

 turned to resume the climb to the point of the 

 disaster — ^but despite the intense excitement, 

 I had not climbed fifty steps before the former 

 inability to lift the feet returned. So I re- 

 mained in virtually helpless condition (send- 

 ing my Indian up to the climbing party with 

 specific inquiries) for perhaps half an hour; 

 when the Indian returned with the gratifying 

 intelligence that " El Gringo " had come to 

 life and had gone on up the mountain — for it 

 appeared that he had merely swooned under 

 the stress of the long walk and the early stages 

 of a stiff climb, and, recovering, had gone on 

 with his accustomed persistence. This epi- 

 sode marked the first observed abnormality in 

 locomotory powers which had been above the 

 average. 



